BANDITS  APPLICATIONS*^ 


C.  L.  CORY. 


GIFT  OF 

Professor  C,  L.  Cory 


ENGINEERING  LIBRARY 


C.  L.  CORY. 


C.L.CORY, 


C.  L.  CORY. 


The  Electric  Motor 


JD  ITS  APPLICATIONS. 


BY 

T.    C.    MARTIN     and     JOSEPH     WETZLER. 


THIRD    EDITION 


THE   DEVELOPMENT  OF  THE   ELECTRIC  MOTOR   SINCE  1888. 

A' 


DR.  LCCtJIS  BELL, 

EDITOR  OF    '<O?HE  ELECTRICAL  WORLD.' 


NEW     YORK: 

THE  W  j.  JOHNSTON  COMPANY,  L'T'D, 

BUIL1JING. 
1891. 


IE  Li 


COPYRIGHT,   1886,   iSSS  und  1891, 
\V.   J.  JOHNSTON. 


PREFACE  TO  THE   THIRD   EDITION. 


'"PHE  two  previous  editions  of  this  work  have  served  such  a  useful  purpose,  and 
•*•  have  so  thoroughly  covered  the  development  of  the  practical  electric  motor  to 
about  the  year  1888,  that  in  issuing  this  third  edition  no  attempt  whatever  has  been 
made  to  revise  the  text  of  the  work.  In  the  last  two  years  the  theory  of  the  elec- 
tric motor  has  come  to  be  better  understood,  and  practice  has  undoubtedly  improved, 

• 

but  the  efforts  of  the  earlier  inventors  and  their  explanations  of  their  own  work  are 
now  a  matter  of  history,  and  the  record  of  them  should  be  preserved.  In  arranging 
this  third  edition,  however,  it  became  necessary  to  add  to  it  a  brief  appendix,  deline- 
ating, in  a  way  necessarily  somewhat  sketchy,  the  growth  of  the  electric  motor  up  to 
the  present  time.  The  machine  itself  has  been  improved  in  various  ways  as  the  prin- 
ciples of  construction  of  dynamo-electric  machines  have  become  more  widely  known, 
and  the  use  of  the  motor  in  modern  industry  has  increased  to  an  extent  little  short 
of  marvelous.  Probably  not  less  than  25,000  motors  are  in  operation  to-day  in  the 
United  States  alone,  while  the  electric  railwa^rs  that  could  have  been  counted  on  the 
fingers  in  1888,  have  now  increased  in  number  to  something  like  300,  operating  over 
more  than  2,000  miles  of  track.  It  is  especially  this  field  of  electric  traction  in  which 
the  motor  has  come  into  use  since  the  last  edition  of  this  book  was  issued,  and  hence, 
in  reviewing  the  progress  that  has  been  accomplished,  it  is  electric  traction  to  which 
attention  has  been  especially  called.  The  stationary  motor  has  been  given  brief  con- 
sideration, and  it  has  been  thought  wise  to  describe  a  comparatively  small  number  of 
typical  forms  rather  than  to  make  an  attempt  to  catalogue  the  efforts  of  inventors  in 
this  particular  line.  It  would,  indeed,  be  difficult  to  keep  track  of  the  course  of  in- 
vention in  producing  slight  modifications  of  existing  motors,  or  in  devising  unusual 
details  of  winding  and  mechanical  construction.  The  electric  motor  to-day,  whether 
for  stationary  or  traction  purposes,  differs  from  its  predecessors  only  in  more  careful 
mechanical  construction  and  better  electrical  design.  The  great  tendency  throughout 
has  been  towards  simplicity  and  slow  speed,  the  latter  having  been  enforced  in  railway 
motors  by  hard  experience. 


842501 


iv  PREFACE. 

Comparatively  little  has  been  said  with  reference  to  foreign,  motors  and  motor 
systems ;  first,  because  the  use  of  the  motor  has  not  increased  abroad  to  anything  like 
the  same  extent  as  here  ;  and  second,  because  rapid  improvement  has  not  been  com- 
pelled by  necessity  as  it  has  been  in  America.  An  exception,  however,  has  been 
made  in  favor  of  the  City  and  South  London  Railway,  as  it  exhibits  a  very  advanced 
type  of  apparatus  for  electric  traction ;  a  model  that  might  often  be  followed  to  advan- 
tage here.  The  lesson  of  that  successful  experiment  has  done  much  to  spur  on 
American  electrical  engineers,  and  is  at  least  the  proximate  stimulus  that  has  pro- 
duced the  recent  gearless  motors  for  electric  railway  service. 

L.  B. 
June,   1891. 


CONTENTS. 


PAGE 

CHAPTER     I.  Elementary  Considerations,                  ...                  ......  1 

"         II.     Early  Motors  and  Experiments  in  Europe,        .                  8 

"        III.  Early  Motors  and  Experiments  in  America,      ......                  .13 

'•'        IV.     The  Electrical  Transmission  of  Power, 29 

V.  The  Modern  Electric  Railway  and  Tramway  in  Europe,           .....  48 

"        VI.  The  Modern  Electric  Railway  and  Street  Car  Line  in  America,  Cl 

"      VII.  The  Use  of  Storage  Batteries  with  Electric  Motors  for  Street  Railways,          .         .  99 

"    VIII.  The  Industrial  Application  of  Electric  Motors  in  Europe,        .....  114 

"        IX.     The  Industrial  Application  of  Electric  Motors  in  America, 125 

X.     Electric  Motors  in  Marine  and  Aerial  Navigation, 137 

XT.     Telpherage, .                  ...  143 

XII.  Latest  American  Motors  and  Motor  Systems,    ........  152 

••    XI1T.     Latest  American  Motors  and  Motor  Systems — Continued 19G 

XIV.     Latest  European  Motors  and  Motor  Systems, 246 

"       XV.     Alternating  Current  Motors, 255 

"    XVI.  Thermo-Magnetic  Motors,  ......                           ....  272 

APPENDIX.  The  Development  of  the  Electric  Motor  since  1888,    ....                          .  279 


LIST  OK   ILLUSTRATIONS. 


FIG.  1. 
"  2. 
"  3. 

"  4. 

"  5. 

"  6. 

"  7. 

"  8. 

"  9. 

"  10, 

"  12, 

"  14. 

"  15, 

ft  i  >*< 

*l> 

"  19, 
"  21, 
"  23. 
"  24. 
"  25, 
"  27. 
"  28, 
"  31. 
"  32. 
"  33. 
"  34. 
"  35. 
"  36. 
•'  37. 
"  38. 
"  39. 

"  40. 
"  41. 
"  42. 
"  43. 
"  44. 
"  45. 

"  46. 

"  47. 
"  48. 


Oersted's  Experiment, 

Field  of  Force  Around  Two  Wires      * 

Diagram  Showing  Constancy  of  Speed 
Under  Varying  Loads 

Jacob  i  Motor       . 

Froment  "         . 

Du  Moncel  Motor       . 

Bourbouze       "  .         .         . 

Pacinotti  . 

Davenport      " 
11.     Walkly      "  . 

13.     Stiinpson  "  . 

Cook  "  . 

16.     Lillie 

18.     Neff  "  ... 

20.     Avery        "  . 

22.     Gustin       "  . 

Page  "  .         .         .         . 

Hall  Locomotive  of  1850-1, 
26.     Page  Motor, 

Stein  Motor  with  Fan, 
29,  30.     Vergnes  Motor, 

Modified  Vergnes  Motor.     . 

Yeiser  Motor,     . 

McCullough  Motor,    .         .         .        . 

Gaume  "         .         .         .         . 

tt  (t 

Wickersham      "          . 
Mason  "          . 

De  Morat  . 

Schuckert  Installation  at  tlie  Munich 

Exposition  of  1882, 
Diagram,    .         . 


Deprez  Generator  at  Miesbach,  . 

Deprez  Installation  at  Munich  Exposi- 
tion, 1882, 

Deprez  Generator  at  the  Chemin  de 
Fer  du  Nord,  Paris,  1883, 

Deprez  Generator  at  Creil,  1885, 

Siemens  Dynamo  with  Dolgorouki 
Engine, 


PAGE 

1  Fir,.  49.   The    Water    Power   of  the    Portrnsh 

2  Railroad,          .         .  . 
"  50,  51.  Tunnel  for  Vienna  Electric  Rail  w'y 

4  "  52.  Elevated  Structure  for  Vienna  Railw'y 

9  "  53.  The  Brighton,  Eng.,  Electric  Rail  way, 

10  "  54,  55.  The  Paris  Electric  Street  Railway 

10  of  1881,  ...... 

11  "  56.  The  Electric  Railway  at  the   Vienna 

12  Electrical  Exposition,      .         .         . 

13  "  57.  Blackpool,  Eng.,  Electric  Street  Car, 

14  "  58.   Details  of  Conductor  Conduit,  .         . 

15  "  59.  Section  of  Roadway,  .... 

15  "  60.   Plan  of  Car,        ..... 

16  "  01.  Generator  at  Blackpool,      ... 
16,  17  "  62.  Exciter,      "                          ... 

17  "  63.  The      Electric      Locomotive,     "The 

18  Judge,"  ...... 

19  "  64.  Track  of  Electric  Railway,   Chicago 

20  Imposition,  1883,     .         . 

21  "  65.   "  The  Judge,"  Side  Elevation,    .         . 

21  "  66.   Plan  View  of  "  The  Judge,"       .         . 

22  "  67.  Rear  Elevation  of  "  The  Judge,"       . 

23  "  68.  Speed  Regulator,        .         .  . 

23  "  69.   Reversing  Mechanism,         .         .         . 

24  "  70.  Early  Edison  Electric  Locomotive,     . 
24  "  71.       "           "           "                 "                . 

24  "  72.  Improved  Edison  Electric  Locomotive 

25  "  73.   Daft  Electric  Locomotive  "  Ampere," 

26  "  74.   Plan  of  "Ampere,"   .... 

27  "  75.  Elevation  of  "  Ampere,"    ... 
"  76.   Method  of  Rail  Insulation,          .         . 

32  "  77.  Daft  Motor,  "  Morse,"       .                 . 

34  "  78.  Details  of  Motor  "  Morse,"         .         . 

34  "  79.  Curve  on  the  Baltimore  Electric  Street 

35  Railway.  ...  . 

36  "  80.  Overhead     Conductor     on    Baltimore 
39  Railway,  ..... 

"  81.  Side   Elevation   of   Daf-t   Locomotivi- 

4d  "Benjamin  Franklin,"   ... 

"  82.  Plan  of  the  "  Benjamin  Franklin,"    . 

41  "  83.  Rear    Elevation    of   the    "  Benjamin 

42  Franklin,"       ...  . 
"  84.  Summer  View  on  Bentley-Knight  Elec- 

49  trio  Street  Railway,  Cleveland,  0., 


51 
52 
52 
53 

54 

56 
58 
58 
58 
58 
59 
60 

63 

64 
64 
64 
Co 
66 
67 
68 
69 
70 
71 
72 
72 
73 
74 
75 

76 

77 

78 
79 

80 


LIST   OF   ILLUSTRATIONS. 


vn 


FIG.  85. 

Winter  View  on  Bentley-Knight  Elec- 

FIG 

.121. 

tric  Street  Railway,  Cleveland,  0., 

84 

tt 

122. 

ef 

86. 

Elevation  of  Proposed  Bentley-Knight 

f( 

123. 

Six  Hundred  and   Seventy   Horse 

tt 

124. 

Power  Electric  Locomotive,  . 

85 

{( 

125. 

ft 

87. 

Standard    Section  of    the    Proposed 

(f 

126. 

Underground  Electric  Railway  for 

(t 

127. 

New  York,     ..... 

00 

(t 

128. 

ft 

88. 

Station  near  14th  Street  on  Proposed 

(C 

120. 

Underground  Electric  Railway  for 

(f 

130. 

New  York,     ..... 

91 

(f 

131, 

ft 

SO. 

Method   of   Making   Pipe  and   Wire 

(C 

133. 

Connections,          .... 

02 

t( 

134. 

tt 

90. 

Van  Depoele  Generator,    . 

03 

1  1 

135. 

tt 

91. 

Large  Van  Depoele  Motor, 

04 

ft 

136. 

tt 

02. 

Van  Depoele  Electric  Railway,  Toron- 

(C 

137. 

to,  Can.,         ..... 

% 

tt 

138. 

ft 

93. 

Minneapolis    Railway,    Van    Depoele 

(f 

139. 

System,           .         . 

95 

(( 

140. 

ft 

9*. 

Electric  Street  Railway,  Montgomery, 

f( 

141. 

Ala.,  Van  Depoele  System,    . 

00 

tt 

142. 

ft 

95; 

Electric  Street  Railway,  Montgomery, 

f£ 

14:5. 

Ala.,  Van  Depoele  System,    . 

00 

ft 

00, 

07.     Pendleton  Method  of  Attaching 

tt 

144. 

Motors  to  Cars,      .... 

97 

ft 

08. 

Locomotive  Driven  by  Accumulators, 

tt 

145. 

Lisieux,  France,    .... 

100 

(f 

146. 

ft 

00. 

Car  Used  with  Accumulators,  Paris  . 

101- 

f£ 

147. 

tt 

100. 

Tin-  Kew  Bridge  Experiment,   . 

102 

(( 

148. 

tt 

101. 

Reekenzaun  Car,  Elevation, 

103 

ti 

102. 

"     Plan, 

103 

ft 

103, 

104.     Gearing  of  Elieson  Car,    . 

100 

tt 

149. 

ft 

105. 

Klieson  Car  with  Accumulators. 

110 

tt 

J06. 

Reckenzaun  Mining  Locomotive, 

111 

ft 

150. 

t  : 

107. 

Charging  Station,  Hamburg  Electric 

s% 

151. 

Street  Railway,      .... 

112 

1  1 

152. 

tt 

108. 

Car,  Hamburg  Electric   Street  Rail- 

t  ( 

153. 

wav, 

11  '5 

tt 

154. 

it 

100. 

Jablochkoff  Motor,  .... 

114 

(  ( 

155. 

it 

110. 

Diagram,  ...... 

114 

tt 

156. 

1  1 

111. 

Deprez's  Small  Motor, 

115 

ti 

157. 

it 

lid. 

a             tt           a 

110 

tt 

158. 

tt 

113. 

Egteve  Motor,  ..... 

117 

tt 

159. 

tt 

114. 

Diagram,  ...... 

117 

it 

160. 

.  . 

115. 

Reckenzaun  Motor,  .... 

110 

tt 

161. 

(t 

110. 

Gramme  Motor  with  Taverdon  Drill. 

120 

tt 

162. 

tt 

117. 

Lee-Chaster  Motor,     .... 

122 

a 

163. 

it 

118. 

Ayrton-Perry     " 

122 

tt 

164. 

ft 

110. 

Details  of  Ayrton-Perrv  Motor. 

123 

it 

165. 

ft 

120. 

Regulator  of     "         '•'           "     . 

123 

a 

166. 

Regulator  of  Ayrton-Perry  Motor,     . 
The  Griscom  Motor,  .... 
Daft  Generator  of  1884,     . 
New  Daft  Generator, 
Daft  Motor  with  Gearing, 
"      with  Blower,    . 
New  Daft  Motor,        .... 
Daft  Motor,  Limit  Switch, 

Details  of  Limit  Switch,   . 
ft       tt       K          tt 

132.  Small  Van  Depoele  Motor, 
Diehl  Motor, 

ft  (C 

Keegan   " 

Pendleton  Motor,        .... 

Armature  of  Pendleton  Motor,  . 

Pendleton  Motor,       .... 

View  of  the  Tissandier  Balloon, 

Batteries  of  Tissandier        " 

The  Krebs-Renard  "      . 

Diagram  of  Telpherage  Tracks, 

View  of  "  Series "  Telpher  Road, 
Weston,  England,  .... 

View  of  "  Cross-Over  Parallel  "  Tel- 
pher Road,  Glynde,  England, 

Diagram  of  Glynde  Track, 

Telpher  Governor,  .... 
"  Brake,  .  .  .  . 

Chandler  System  of  Suspension  Trans- 
portation, Elevation  of  Locomotive 
Car, 

Chandler  System  of  Suspension  Trans- 
portation, End  View  of  Car,  . 

Small  Freight  Car,  Chandler  System 

Motor  on  Chandler  Wire  Road,  . 

Passing  a  Pole  on  Chandler  Wire  Road 

Design  for  Mail  or  Coast  Service 

Van  Depoele  Telpher  System,    . 
ft  a  t(  tt 

The  Stockwell  Motor, 
Armature  of  Stockwell  Motor,  . 
Perspective  of  Resistance  Board, 
Diagram  of  Resistance  Bars, 

Beattie  Motor, 

Details  of  Beattie  Armature, 
Brush  Motor,       ..... 

Details  of  Governor,  Brush  Motor,   . 

tt       tt  it  it  tt 

The  C.  &  C.  Motor,     . 

Sprague  Electric    '•  ... 


PAGE 

124 
126 
127 
128 
128 
129 
130 
131 
131 
131 
132 
133 
134 
134 
134 
135 
135 
139 
140 
141 
143 

144 

145 
146 
146 
146 


147 

148 
148 
149 
149 
149 
150 
150 
152 
153 
153 
153 
154 
154 
155 
156 
156 
156 
100 


VJ11 


LIST  OF   ILLUSTRATIONS. 


Fir,. 


167. 
168. 
169. 
170. 

171. 

172. 

173. 

174. 

174« 

175. 

176. 

177. 

178. 

179. 

180. 
181. 

182. 

183, 
185. 

186. 
187. 
188. 
189. 
190. 
191. 
192, 
194. 

195. 
196. 

197. 
198. 

199. 
200. 
201. 

202. 
203. 


Sprague  Electric  Motor, 


Spraguo  Electric  Railway  System, 
One-car  Train,  .... 

Sprague  Electric  Railway  System, 
Two-car  Train, 

End  View  of  Car,      .... 

Truck  of  Sprague  Car, 

Elevation  of  Sprague  Car  Truck, 

.  Plan  of 

Henry  Electric  Motor  for  Railways, 

S(  if  it  ft  ft 

Side  View,  Higham  Motor, 

Sectional  View  "          "  .        . 

Perspective,  Van  Depoele  Street  Car 
Motor, 

Van  Depoele  Motor,  .... 

Motor  and  Truck,  Field  System,  Side 
Elevation, 

Motor  and  Truck,  Field  System,  End 
Elevation,  .  .  .  .  . 

184.  Bearing  of  -Motor  on  Car  Axle, 

Regulating  Motor  and  Adjustable 
Brushes, 

Details  of  Commutator,     . 

Details  of  Brush-holder,    . 

The  "  Berkshire  "  Electric  Car, 

The  Schlesinger  Electric  Car,    . 

The  Edgerton  Motor, 

Sectional  View  of  Edgerton  Motor,    . 

193.  The  Fisher  Motor,      . 

Standard  Truck,  Bentley-Knight 
System, 

Car  Mounted  on  Standard  Truck, 
Bentley-Knight  System, 

Double  Motor  Truck,  Bentley- 
Knight  System,  .... 

Car  Mounted  on  Double  Motor 
Truck,  Bentley-Knight  System,  . 

Motor  Car  and  Tow,  Conduit  Cross- 
ing, Bentley-Knight  System, 

Conduit,  Bentley-Knight  System, 

Contact  Plow, Bentley-Knight  System, 

Contact  Trolley,  Elevated  Con- 
ductors, ..... 

Elevated  Conductors  Supported  by 
Posts  and  Brackets  at  Curb, 

Elevated  Conductors  Supported  over 
Centre  of  Roadway, 


PAGE  PACE 

.167      FIG.  204.     Field's   Electric    Locomotive — Per- 

168  spective, 204 

169  "     205.     Field's     Electric     Locomotive — In- 

terior of  Cab,        .         .         .         .205 

172  "     206.     Field's    Electric    Street    Railway- 

Double  Conduits  and  Tracks  Com- 

173  bined, 206 

174  "     207.     Field's     Electric     Street      Railway 

175  System, 207 


176  "  208.     Longitudinal  Section,  Field  Conduit 

177  Arrangement,       ....     208 

181  "  209.     Transverse  Section,  Field  Conduit 

182  Arrangement,       ....     208 
182        "  210.     Plan  View,  Field  Conduit  Arnuiirc- 

182  ment, 208 

"  211.     The  Field  Electric  Street  Car,        .     209 

183  "  212,213.     Details  of  Short-Nesmith  ( 'on- 

184  duit  for  Series  Working,       .         .     210 
"  214.     Collecting   Bar    of    Short-Nesmith 

185  Conduit  for  Series  Working,         .     211 
"  215.     Perspective  of  Bar  of  Short-Nesmith 

186  Conduit  for  Scries  Working,         .     211 

187  "  216.     Diagram  of  Circuit  Connections,     .     211 
"  217.  .     212 

188  "  218.     Cross  Section  of  Conduit  and  Track. 

189  Denver,  Col.,        .         .         .         .    '213 

190  "  219.     Motor  and  Truck— Denver  Klcctric 

191  *  Railway,       .        .         .        .        .     214 

192  "  220.     Motor  Car   of   the  Fisher  Electric 

193  Railway,       .         .         .         .         .215 

193  "  221.     Fisher  Electric  Motor,    .         .         .     •-'!:> 

194  "  222.     Irish's  Electric  Railway  System,     .     210 
"  223,  224.     Details  of  Irish's  Electric  Rail- 

197  way  System,         .         .         .         .216 
"  225,  226.     Details  of  Irish's  Electric  Ilail- 

198  way  System,         .         .         .         217-18 
"  227.     Schlesinger   Motor  for  Locomotive 

190  Work,  .  .         .     220 

"  228.     Schlesinger   Motor  for  Locomotive 

200  Work, 2->l 

"  220.     Schlesinger  Railway  Motor-Plan,    .     222 

201  •'  230.     Locomotive  on  the  Schlesinger  Elec- 

202  trie  Road,  Lykens  Valley  Mine,  .     223 

203  "  231.     View  of  Train  at  the  Mouth  of  the 

Mine, 2 -.'4 

203         "  232.     The  Julien  Electric  Street  Car,       .     225 

"  233.     Fifteen  II.  P.  Electric  Motor  of  the 
203  Thomson-Houston  Company,       .     •.'•.''; 

"  234.     Small    Baxter   Motor   for  Arc  Cir- 
203  cuits,    .         .         .         .         .         .2^7 


LIST  OF  ILLUSTRATIONS. 


IX 


Mo- 


Mo- 


FIG.  235.     Large   Baxter   Motor   for  Arc  Cir- 
cuits,  ...... 

"     230.     Large  Baxter  Motor  for  Incandes- 
cent Circuits,       .... 

"     237.     The  C.  &  C.  Motor, 

"     238.     The  C.  &  C.  Armature,  . 

"     239.     The  C.  &  C.  Armature  Winding,  . 

"     240.     C.  &  C.  Shunt  Wound  Motor, 

"     241.     New  C.  &  C.  Shunt  Wound  Motor, 

"     242.     C.  &  C.  Motor,        .... 

"  .243.     Small  C.  &  C.  Motor,  with  Wheeler 
Regulator,    ..... 

"     244.     The  Lugo  Motor,    .... 

"     244rt,  244 b.     The  Lugo  Motor, 

"     244r,  244d,  244e.     The  Lugo  Motor, 

"     244/.     The  Lugo  Motor, 

••     245.     Patten's  Electric  Motor, 

"     240,247.      Patten's  Electric  Motor,  . 

"     248.     New  Ilochhauscn  Motor, 

••     249,  250.     The  Hyer  Electric  Motor, 

"     251.     The  Thone  Electric  Motor,     . 

"     252.     The  Card   Constant-Potential 

tor, 

"     253.     The   Card    Constant-Current 

tor,       ...... 

"     254.     Armature  of  Card  Motor, 
"     255.     Diehl    Combined    Sewing-Machine 
and  Motor,  ..... 

"     250.     Field  Magnet  of  Diehl  Motor, 

"     257.     Details  of  Diehl  Armature  Winding, 

"     258.     Pollak   and   Binswanger's   Electric 

Railway, 
"     259.     Pollak    and 

Railway, 
"    200.     Pollak   and 

Railway,       ..... 

"     261.     Details  of  Pollak  and  Binswanger's 
Electric  Railway,  .... 

"    202.     The  Immisch  Motor, 
"     263.       "          "  "  ... 

"     204,  205.     Rowan  Riveting-Machine, 
"     206.     Rowan  Drilling-Machine, 
"     267.         "       Chipping-Machine       . 
"     268.         "       Calking-Machine, 
"     269.         "       Electric  Calking-Machine,  . 
•   "     270.     The  Brown  (Oerlikon)  Motor, 
"     271.     Transmission  of  Power  by  Oerlikon 
Machines,     ..... 

"'     272,  273.     The  Brown  Dynamo, 
"     274,  275.     Thomson    Alternating    Motor 
Experiments,        .... 


Binswanger's   Electric 
Binswanger's   Electric 


PAGE  PAGE 

FIG.  276,  277.     Thomson    Alternating    Motor 

228  Experiments,        ....  258 
"  278,  279.     Thomson    Alternating    Motor 

229  Experiments,        ....  259 

230  "  279a,  2796.     Thomson  Alternating  Motor 

231  Experiments,        ....  260 
231         "  280,281,282.     Patten    Alternating-Cur- 

234  rent  Motor,  .         .         .         .261 

234  "  283,  284.     Duncan     Alternating-Current 

235  Motor  Experiments,     .         .         .  262 
"  285.     Duncan    Alternating-Current    Mo- 

235  tor  Experiments,  .         .         .263 

236  "  280.     Duncan    Alternating-Current    Mo- 

236  tor  Experiments,           .         .         .  263 

237  "  287.     The  Tesla  Alternating-Current  Mo- 

238  tor, 265 

238        "  288,  288a.              "              "              "  265 

238-9        "  289,  289«.             "              "               "  265 

241  "  290,  290«.              "              "               "  266 

242  "  291,  291a.              "                               "  266 

242  "  292,  292«.              "              "               "  266 
"  293,  293rt.              "               "               "  266 

243  "  294,  294rt.                              "               "  266 
"  295,  295a.              "              "               "  267 

243  "  296.                        "              "               "  267 

244  "  297.                                        "               "  267 
"  298.                        "               "               "  267 

244        "  299.                        "              "               "  269 

244        "  300.                        "              "              "  269 

244        "  301.                        "              "              "  270 

"  302.                        "              "              "  270 

246  "  303.                        "              "              "'  270 
"  304.                        "              "  '  271 

247  "  305.                        "                               "  271 
"  306.                        "                              "  271 

247        "  307.                       "              "              "  271 

"  308.     Thomson    and    Houston's  Experi- 

247  mental  Pyromagnetic  Motor,        .  273 

248  ••  309.     McGee's  Pyromagnetic  Motor,         .  273 

248  "  310.     Schwedoff's  Therrno-Magnetic  Mo- 

249  tor,       , 274 

249  "  311.     Edison's  Pyromagnetic  Motor,        .  275 

250  "  312.                              "                 "               .  275 
250         "  313.     Menges'   Pyromagnetic   Generator- 

250  Motor, 276 

251  ••  314.     Menges'   Pyromagnetic   Generator- 

Motor,          276 

252  '•  315.     Menges'   Pyromagnetic   Ge?ierator- 

253  Motor, 277 

"  310.     Menges'   Pyromagnetic    Generator- 

257                             Motor, 277 


LIST  OF  ILLUSTRATIONS. 


FIG.  317. 

"  318. 

"  319. 

"  320. 

"  321. 

"  322. 

"  323. 

"  324. 

"  325. 

"  326. 

"  327. 

"  328. 

"  329. 

"  330. 

"  331. 

"  332. 

"  333. 

"  334. 


335. 


PAGE 

Early  Sprague  Motor  Truck,  .  .  279 
Sprague  Switch  Box,  .  .  .280 
Later  Sprague  Motor  Truck,  .  .  280 
Thomson-Houston  Motor  Truck,  .  281 
Thomson-Houston  Rheostat,  .  .  282 
Short  Railway  Motor,  .  .  .  282 
Short  Motor  Truck,  .  .  .283 
Westinghouse  Street  Railway  Mo- 
tor,    284 

Rae  Motor  Truck,  .  .  .286 
Wenstrom  Railway  Motor,  .  .  288 
Section  of  Hydraulic  Clutch,  .  .  289 
Hydraulic  Clutch  in  Position,  .  289 
Baxter  Motor  Truck,  .  .  .  290 
Thomson-Houston  Slow  Speed  Mo- 
tor,    291 

Details  of  Thomson-Houston  Slow 

Speed  Motor,       .         .                 .  292 

Westinghouse  Slow  Speed  Motor,    .  293 
Field    Magnets    of    Westinghouse 

Slow  Speed  Motor,        .  .294 

Magnetizing  Coil  and  Brush  Holder 
of    Westinghouse     Slow     Speed 

Motor, 295 

Gear  Casing  of  Westinghouse  Slow 

Speed  Motor,       ....  295 


PAGE 

FIG.  336.     Westinghouse  Gearless  Railway  Mo- 
tor,   296 

"    337.     The  Short  Gearless  Motor,      .         .  297 
"    338.     Plan  of  Short   Gearless   Motor   in 

Position  on  the  Truck,         .         .  298 
'•'    339.     Electric    Locomotive   on    City  and 

South  London  Railway,      .         .  300 

"    340.     Twenty-five  Kilo-watt  Edison  Motor,  302 

"     341.     Connections  of  Edison  Motor,         .  303 

"    342.     Edison  Self  Oiling  Bearing,     .         .  303 
"    343.     Detail    View    of    Crocker-Wheeler 

Motor, 303 

"    344.     Five  Horse-power  Crocker-Wheeler 

Motor, 304 

"    345.     Crocker- Wheeler  Self  Oiling  Bear- 
ing,        304 

"    346.     Crocker- Wheeler  Fan  Motor,  .         .  304 

"    347.     Crocker- Wheeler  Starting  Switch,  .  305 
"     348.     Small     Crocker- Wheeler     Constant 

Current  Motor,  ....  305 
"  349.  The  Connecticut  Motor,  .  .  300 
"  350.  The  Eddy  Motor,  ....  306 
"  351.  The  United  States  Motor,  .  .  307 
"  352.  Perret  Multipolar  Motor,  .  .  308 
"  353.  Magnetic  Circuit  of  Perret  Multi- 
polar  Motor,  ....  309 


THE    ELECTRIC    MOTOR 


AND    ITS    APPLICATIONS. 


_  V* 

CHAPTER 


I. 


ELEMENTARY  CONSIDERATIONS. 


As  the  functions  of  the  electric  motor  are  de- 
pendent upon  the  action  of  the  electric  current, 
it  is  necessary  at  the  beginning  of  the  present 
work  to  give  a  review,  however  brief,  of  the 
principal  facts  involved. 

The  time  is  not  so  very  remote  when  the  ex- 
istence of  an  electric  current  was  chiefly,  if  not 
wholly,  made  manifest  by  effects  other  than 
magnetic.  Up  to  the  year  1820  one  of  the  most 
important  facts  generally  known  was  that  if 
the  circuit  from  a  voltaic  battery  was  completed 
through  acidulated  water,  the  water  was  de- 
composed. Another  interesting  thing  ascer- 
tained was  that  if  a  conductor  were  made  suffi- 
ciently thin,  the  current  would  bring  it  to 
incandescence.  To  these,  we  may  add  the  dis- 
covery of  the  electric  arc  by  Sir  Humphry 
Davy  during  the  first  decade  of  this  century, 
and  that  of  the  reaction  of  the  muscles  and 
nerves  to  the  passage  of  a  current. 

For  many  years  the  idea  had  prevailed,  as 
Prof.  Forbes  puts  it,  that  there  was  some 
"  hidden  connection  between  the  compass  and 
electricity,  between  the  power  that  impelled  the 
compass  to  point  to  the  north  and  the  lightning 
in  the  sky.  It  had  been  believed  that  when 
lightning  had  disarranged  the  compass-needle 
and  reversed  its  polarity,  it  showed  that  there 
was  some  connection  between  electricity  and 
magnetism."  What  this  connection  was  long 
remained  a  matter  of  mere  speculation,  but 
while  carrying  on  some  experiments  with  the 
object  of  solving  the  problem,  Oersted  found 
that  when  the  current  from  a  galvanic  cell  was 
passed  through  a  wire  held  over  a  compass- 
needle  from  the  south  to  the  north,  the  needle's 
north  pole  was  swerved  to  the  west;  see  Fig.  1. 


Thus,  practically,  was  demonstrated  for  the 
first  time  the  correlation  between  electricity 
and  magnetism.  The  experiment  attracted  uni- 
versal attention,  and  gave  to  many  investi- 
gators a  clue  to  follow  up.  It  was  not  long 
after  this  in  the  same  year,  1820,  that  Arago 
and  Davy  discovered,  independently  of  each 
other,  that  iron  and  steel  could  be  magnetized 
by  the  passing  of  a  current  through  a  wire 
wound  around  them;  and  Sturgeon  was  prompt 
to  apply  the  principle  to  the  construction  of 
powerful  electro-magnets. 


FIG.  1. — OERSTED'S  EXPERIMENT. 

It  was  also  noted  by  Barlow,  that  by  passing 
a  current  from  the  centre  to  the  circumference 
of  a  copper  disc  placed  between  the  poles  of  a 
magnet,  the  disc  would  revolve.  This,  familiar 
as  "  Barlow's  wheel,"  was  the  first  electric 
"motor,"  in  the  true  sense  of  the  word. 

Faraday,  in  1831.  recognizing  with  the  insight 
of  genius,  the  relation  and  convertibility  of  the 
phenomena  so  far  observed,  obtained  an  elec- 
tric current  by  electro -magnetic  induction. 
This  grand  discovery  may  be  summarized  in 
the  statement  that  when  a  conductor  in  closed 
circuit  is  made  to  cut  magnetic  "  lines  of  force," 
a  current  is  generated  in  that  conductor.  Far- 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


aday  also  reversed  Barlow's  experiment  and 
obtained  a  current  from  a  copper  disc  rotated 
between  the  poles  of  a  magnet.  But  he  left 
the  application  of  the  fruitful  laws  he  had  dis- 
covered to  others,  who  invented  numerous 
types  of  magneto-electric  generators,  into  a 
description  of  which  it  is  not  needful  here  to 
enter. 

Although  the  reversibility  of  the  electric 
.-.  motor -and "the  magneto-electric  generator  had 
•  already  bee«  noticed,  little  thought,  apparently, 
•was- given  to  the  fact;  and  meantime  the  other 
phenomena  exhibited  in  the  action  of  electro- 
magnets were  employed  in  the  construction  of 
electric  motors,  some  of  which  are  described  in 
subsequent  chapters. 

It  was  not  until  1873,  after  the  substitution  of 
electro-magnets  for  permanent  ones  in  electric 
generators,  that  the  reversibility  of  the  "  dyn- 
amo "  was  fully  recognized  or  realized,  in  the 
action  of  the  Gramme  machines  exhibited  at 
the  Vienna  exhibition  of  that  year.  As  said 
above,  electric  motors  had  been  built  and  oper- 
ated many  years  before  this,  but  they  found  no 
extended  practical  application,  chiefly  because 
they  depended  upon  the  galvanic  battery  for  a 
supply  of  current.  Now,  as  the  energy  devel- 
oped by  the  oxidation  of  a  quantity  of  zinc  of  a 
given  value  in  a  battery  is  far  less  than  that 
which  can  be  obtained  by  burning  a  quantity 
of  coal  of  the  same  value  under  a  steam  boiler, 
it  follows  that  electric  motors  could  not  compete 
with  other  forms  of  motors.  Hence  it  remained 
for  some  cheaper  source  of  current  to  be  discov- 
ered, as  it  was  in  the  dynamo-electric  gener- 
ator. 

With  this  brief  sketch,  intended  to  be  suggest- 
iye  rather  than  exhaustive,  of  the  facts  relating 
to  the  evolution  of  the  electric  motor  of  to-day, 
we  come  to  consider  the  motor  in  regard  to  the 
manner  in  which  it  operates  as  a  machine  for 
converting  electrical  energy  into  mechanical 
energy. 

Beginning  with  the  earlier  forms  of  motors, 
we  note  at  once  several  ways  in  which  the  cur- 
rent can  be  applied  for  mechanical  purposes. 
The  term  "  electric  motor,"  it  should  be  pre- 
mised, includes  all  apparatus  by  which  energy 
in  the  form  of  electric  current  is  converted  into 
mechanical  energy,  through  whose  employment 
work  is  performed,  such  as  the  driving  of  a  fan 
or  a  lathe,  the  raising  of  an  elevator,  the  propel- 
ling of  a  locomotive,  and  the  like.  Thus  we 


may  use  the  attraction  that  an  electro-magnet 
exerts  upon  an  iron  or  steel  armature;  or  the 
mutual  attraction  between  two  electro-magnets. 
These  and  analogous  principles  are  evidently 
based  upon  the  attractive  force  exhibited  be- 
tween masses  of  magnetic  metal. 

In  the  practical,  commercial  motor  of  to- 
day, however,  the  action,  though  apparently 
similar  to  the  above,  is  quite  different.  It  de- 
pends upon  the  principle  that  when  a  current 
passes  through  a  wire,  the  latter  becomes  sur- 
rounded by  a  field  of  force  similar  in  nature  to 
that  pertaining  to  ''  permanent "  magnets.  This 
is  clearly  shown  in  Fig.  2,  which  represents  a 
plate  through  which  two  wires  pass,  the  lines 
of  force  being  exhibited  by  the  positions  as- 
sumed by  the  iron  filings  sprinkled  upon  the 


FIG.  2. — FIELD  OF  FOKCE  AUOUND  Two  WIRES. 

surface  of  the  plate.  As  will  be  observed,  the 
lines  of  force  encircle  the  wire,  and  when  such 
a  wire  is  brought  into  the  vicinity  of  a  magnet, 
it  acts  to  all  intents  and  purposes  as  if  it 
were  a  magnet  having  circular  lines  of  force 
at  all  points  in  planes  at  right  angles  to  its 
length. 

Now,  if  the  current  in  the  wire  is  in  a  certain 
direction,  these  lines  of  force  will  appear  to  cir- 
culate from  left  to  right;  and  with  the  current 
in  the  contrary  direction,  from  right  to  left. 
The  wire  in  this  condition,  when  brought  in 
proximity  to  a  magnet,  is  attracted  or  repelled 
in  the  same  way  as  if  it  were  a  magnet,  the  at- 
traction or  repulsion  being  determined  by  the 
direction  in  which  the  lines  of  force  circulate- 
in  other  words,  according  to  the  direction  of  the 
current. 


ELEMENTARY  CONSIDERATIONS. 


The  action,  then,  in  the  majority  of  electric 
motors  of  to-day  is  primarily  that  exhibited  be- 
tween a  magnet  and  a  wire  carrying  a  current, 
and  is  the  reverse  of  the  action  seen  in  the 
magneto-electric  or  dynamo  -  electric  machine. 
In  the  magneto  and  dynamo,  the  motion  of  a 
conductor  generates  current;  in  the  former,  a 
current  in  the  conductor  produces  motion.  In 
the  dynamo,  it  requires  mechanical  power  to 
force  the  wires  through  the  magnetic  field,  in 
order  to  generate  current,  and,  according  to 
Lenz's  law,  the  currents  generated  have  a  direc- 
tion such  that  their  reaction  upon  the  magnet 
tends  to  stop  the  motion  which  produces  them. 
Conversely,  in  the  motor  it  is  the  current  acting 
upon  the  magnet  that  produces  mechanical 
power.  In  this  case,  however,  the  reactions  of 
the  current  being  free  to  exert  their  power,  the 
motion  obtained  will  be  the  opposite  of  that  in 
the  dynamo.  Hence  we  understand  why  a  dyn- 
amo set  to  work  as  a  motor,  runs  in  the  reverse 
direction,  where  the  construction  of  the  ma- 
chine is  such  that  the  polarity  of  the  field  mag- 
nets remains  the  same  in  both  functions  of 
generator  and  motor. 

It  was  said  above  that  the  action  in  nearly 
all  the  motors  of  to-day  is  due  primarily  to  the 
reaction  between  magnet  and  current,  in  con- 
tradistinction to  that  exhibited  in  the  older  mo- 
tors, which  operated  by  the  attraction  of  mag- 
netized iron  or  steel.  But  as  the  modern  motors 
have  iron  in  their  armatures,  the  question  may 
be  asked,  What  is  the  object  in  putting  it  there? 
The  answer  is,  that  by  the  presence  of  the  iron 
the  magnetic  lines  of  force  are  strongly  con- 
centrated upon  the  wires.  Dynamos  will  gen- 
erate current  and  motors  will  perform  work 
without  the  presence  of  an  iron  core  in  their 
armatures,  but  both  are  less  efficient  when  so 
constructed. 

Let  us  now  see  what  takes  place  when  the 
electric  motor  starts  to  work.  We  will  sup- 
pose, for  the  sake  of  simplicity,  that  a  galvanic 
battery  is  connected  with  a  motor,  and  that  a 
galvanometer  is  interposed  in  the  circuit.  If 
now  we  clamp  the  motor  down  so  that  it  cannot 
revolve,  and  hence  cannot  do  work,  we  get  a 
certain  strength  of  current.  If  we  then  release 
the  motor  so  as  to  allow  it  to  revolve,  we  find 
that  as  the  speed  of  the  armature  increases,  the 
current  decreases.  This  fact  was  observed  by 
the  earliest  experimenters  with  electric  motors, 
and  not  being  correctly  interpreted  was  consid- 


ered one  of  the  greatest  drawbacks  to  success- 
ful operation,  for  it  was  believed  at  that  time 
that  as  the  motor  revolved  it  created  a  resist- 
ance which  tended  to  diminish  the  current.  It 
was  argued,  therefore,  that  the  electric  motor 
was  necessarily  a  wasteful  machine.  We  know 
to-day  that  this  is  by  no  means  the  case,  and 
that  the  action  observed  in  the  electric  motor  is 
one  upon  which  its  true  value  as  a  working  and 
useful  machine  depends.  Jacobi  was  the  first 
to  point  out  that  the  diminution  of  current  irrdi- 
cated  by  the  galvanometer  was  not  due  to  re- 
sistance engendered  by  the  motor,  but  was  due 
to  a  counter-electromotive  force  generated  by 
it.  This  is  easily  understood  when  we  consider 
that  the  motor,  in  revolving  in  a  direction  oppo- 
site to  that  of  the  generator,  creates  a  current 
in  the  other  direction.  The  opposing  current, 
of  course,  lessens  the  original  current.  We 
may  here  appropriately  and  correctly  apply  the 
converse  of  Lenz's  law  above  quoted,  and  say 
that  the  motion  produced  is  always  such  that 
by  virtue  of  the  magneto  -  electric  induction 
which  it  sets  up,  it  tends  to  stop  the  current. 
From  his  observations,  Jacobi  formulated  the 
important  law  that  when  an  electric  motor  does 
its  greatest  possible  work,  it  diminishes  the 
original  current  one-half;  and  hence  a  loss  of 
50  per  cent,  is  experienced  when  the  motor  is 
exerting  its  greatest  power. 

This  can  be  shown  by  a  simple  illustration. 
Let  us  take  two  machines  exactly  alike  and 
connect  them  up  as  generator  and  motor,  the 
former  being  driven  at  a  constant  speed.  Now, 
if  while  the  generator  is  at  work  we  clamp  the 
motor  so  that  it  cannot  revolve,  no  work  is 
being  done  by  it,  and,  at  the  same  time,  no 
counter  -  electromotive  force  is  generated.  If 
now  we  release  the  motor,  and  allow  it  to  re- 
volve freely,  its  speed  will  gradually  increase 
until  reaching  that  of  the  generator.  But  at 
this  equal  speed  it  will  create  a  counter-electro- 
motive force  equal  to  that  of  the  generator,  so 
that,  practically,  there  will  be  no  current  at  all, 
and,  evidently,  the  motor  will  again  be  incapa- 
ble of  doing  work.  We  see,  therefore,  that  at 
zero  counter-electromotive  force  and  at  max- 
imum counter-electromotive  force,  the  motor 
does  no  work.  The  mean  between  these  two 
limits  is  one-half  the  original  electromotive 
force;  so  that,  as  Jacobi  pointed  out,  the  motor 
is  doing  its  greatest  work  when  the  original 
current  is  reduced  one-half,  i.  e.,  when  the  coun- 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


ter-electromotive  force  is  50  per  cent,  of  the 
original  electromotive  force. 

But  this  law,  relating  only  to  the  maximum 
work  or  activity  of  the  motor,  has  unfortunately 
been  misinterpreted  to  mean  that  the  maxi- 
mum efficiency  of  the  electric  motor  is  50  per 
cent.,  thus  making  it  appear  to  be  a  compara- 
tively inefficient  and  wasteful  machine. 

The  efficiency  of  the  electric  motor  can,  the- 
oretically considered,  be  made  to  include  any- 
thing between  0  and  100  per  cent.  In  order  to 
make  this  clear,  we  will  take  the  same  example 
as  before.  It  has  been  seen  that  when  the  gen- 
erator is  in  operation  and  the  motor  is  clamped 
down,  the  latter  does  no  work,  and  the  current 
is  dissipated  and  wasted  in  heating  the  circuit. 
Hence  the  efficiency,  being  the  ratio  of  the 
power  applied  in  the  generator  to  that  obtained 
from  the  motor,  is  zero.  It  has  also  been  seen 
that  when  the  motor  is  running  without  a  load, 
it  generates  a  counter-electromotive  force  equal 
to  the  original  electromotive  force,  and  reduces 
the  current  in  the  line  to  zero.  But,  evidently, 
with  no  current  existing  it  requires  no  power, 
excepting  that  for  overcoming  friction,  to  drive 
the  generator.  We  thus  have  virtually  no 
power  required  at  the  generator  and  virtually 
none  developed  at  the  motor — which  gives  an 
efficiency  of  100  per  cent.  This,  as  we  have 
seen,  takes  place  when  the  counter-electromo- 
tive force  is  100  per  cent,  of  the  original. 

Now  let  us  put  a  small  load  upon  the  motor. 
Its  speed,  which  has  hitherto  been  equal  to  that 
of  the  generator,  will  be  diminished  in  conse- 
quence, and  hence  the  counter-electromotive 
force  will  fall  off.  This  allows  a  certain 
amount  of  current  to  flow  through  the  circuit, 
and  the  generator  requires  a  certain  corre- 
sponding amount  pf  power  to  drive  it.  If  we 
go  on  increasing  the  load  of  the  motor,  we  re- 
duce, in  equal  degree,  the  speed  and  the 
counter-electromotive  force,  while  increasing 
the  current  and  the  power  necessary  to  ener- 
gize the  generator.  Each  accession  of  current, 
therefore,  means  more  power  applied  to  the 
generator.  But  while  at  100  per  cent,  efficiency 
both  machines  were  running  at  the  same  speed, 
the  increase  in  load  on  the  motor  has  checked 
its  "speed,  and  hence  it  is  not  doing  as  much 
work  as  is  required  to  run  the  generator,  which 
retains  its  original  speed.  It  follows  that  the 
efficiency  can  no  longer  be  100  per  cent.,  but 
must  be  something  less;  and  that  something 


less  is  clearly  the  ratio  between  th&  relative 
speeds  of  the  generator  and  the  motor. 

Now  it  has  been  seen  that  the  counter-elec- 
tromotive force  is  in  direct  ratio  to  the  speed  of 
the  motor.  We  infer,  therefore,  that  the  effi- 
ciency of  an  electric  motor  is  in  direct  ratio  to 
the  counter-electromotive  force  developed.  If 
we  run  a  motor  so  as  to  allow  it  to  develop  a 
counter-electromotive  force  of  90  per  cent.,  its 
efficiency  will  be  90  per  cent.;  and  thus  we 
can,  by  reducing  the  power  developed  by  the 
motor,  increase  its  efficiency  to  any  desired  de- 
gree. It  being  true  also  that  in  order  to  obtain 
the  maximum  power  from  a  motor  we  reduce 
its  efficiency  to  50  per  cent,  it  is  evident  that 
when  we  wish  to  work  with  higher  economy 
we  must  not  tax  the  motor  to  its  full  working 
capacity. 

As  these  principles  are  new  to  many,  we  have 
sought,  even  at  the  risk  of  making  a  labored 
and  reiterative  explanation,  to  state  them  fully. 
A  very  apt  analogy  is  encountered  in  the  work- 
ing of  the  steam  engine,  with  which  greater 
familiarity  exists.  By  letting  the  valve  of  an 
engine  follow  full  stroke,  one  might  admit 
steam  to  the  cylinder  at  boiler  pressure  during 
the  entire  stroke.  This  would  give  a  mean 
effective  pressure  upon  the  piston  equal  to  the 
boiler  pressure  and  would  cause  the  engine  to 
exert  its  greatest  power.  But  this  method  of 
operating  is  not  economical,  and  in  actual 
practice,  the  steam  is  cut  off  at  different  points 
in  the  stroke.  That  of  course  reduces  the  mean 
effective  pressure,  and  hence  the  power  of  the 
engine  below  that  which  it  could  be  made  to 
exert  if  run  uneconomically. 

As  just  said,  we  have  entered  with  careful 
explicitness  into  the  description  of  the  action 
involved  in  the  operation  of  the  electric  motor, 
because  considerable  misapprehension  appears 
to  exist  as  to  the  true  meaning  of  Jacobi's  law. 
We  have  refrained,  as  will  be  noted,  from  any 
mathematical  demonstration  of  these  important 
facts  and  principles,  for  the  reason  that  to  many 
deeply  interested  in  this  subject,  mathematical 
symbols  and  formulae  furnish  no  adequate  pict- 
ure of  the  reasoning  involved. 

In  describing  the  causes  of  the  efficiency  of 
electric  motors,  we  have  assumed  that  the  gen- 
erator and  motor  are  both  perfect  converters  of 
energy;  that  is,  that  the  generator  is  capable  of 
converting  into  electricity  all  the  power  applied 
to  it,  and  that  the  motor  is  capable  of  convert- 


ELEMENTARY  CONSIDERATIONS. 


ing  into  mechanical  power  all  the  electricity 
supplied  to  it  (friction  being  omitted  in  both 
cases).  Now  in  actual  practice  such  is  not  the 
case,  because  all  dynamos  present  resistance 
to  the  current,  which  generates  heat  in  them; 
and  other  causes  besides  friction  tend  to  reduce 
the  efficiency  of  the  machine.  Dynamos  have 
nevertheless  been  built  giving  an  efficiency  of 
over  90  per  cent.,  showing  that  they  are  excel- 
lent converters  of  energy. 

But  it  has  been  found  in  the  past  that 
when  efficient  dynamos  were  employed  as 
motors  their  efficiency  was  reduced  consider- 
ably. This  difference  was  generally  sought  to 
be  explained  by  an  assertion  or  a  supposition 


lilt 
etc 

ttc 

410 
201 

1 

A- 

" 

H.P.  i 


13 


FIG.  3. — DIAGRAM  SHOWING  CONSTANCY  OF  SPEED 
UNDER  VARYING  LOADS. 

that,  having  been  designed  and  made  for  one 
purpose,  the  machine  was,*therefore,  not  suit- 
able for  the  other.  No  satisfactory  explanation 
was  given  of  the  cause  of  this  lower  efficiency 
of  motors,  or,  in  other  words,  of  how  the  miss- 
ing power  is  expended. 

Taking  up  this  question  Mr.  Mordey,  an  able 
English  electrician,  has  recently  shown  the  prin- 
cipal cause  of  this  loss,  which  can  be  readily 
avoided,  and  his  experiments  also  establish  the 
fact  that  a  well  constructed  motor  approaches 
very  closely  in  its  action  the  limit  that  theory 
would  assign,  as  indicated  above.  In  the 
search  for  general  principles,  says  Mr.  Mordey, 
all  those  ways  of  considering  the  actions  which 
depend  on  the  idea  of  magnetic  poles  in  the 
armature  were  abandoned,  and  the  conclusion 
was  arrived  at  that  the  armature  should  have 
no  polar  action  whatever,  that  the  iron  of  the 
armature  should  have  only  the  function  of  a 
conductor  of  lines  of  force,  and  that  the  power 


of  the  motor  should  be  due  to  the  simple  action 
between  the  lines  of  force  of  the  magnetic  field 
and  the  armature  wires  conveying  currents  at 
right  angles  to  those  lines  of  force.  This  mode 
of  regarding  motor  action  is  convenient  on  sev- 
eral grounds,  and  leads  to  certain  conclusions, 
which,  if  correct,  form  substantial  bases  for 
practical  construction.  Thus  the  armature,  in- 
stead of  being,  as  hitherto,  considered  as  a 
strong  electro-magnet  placed  in  the  field  of  an- 
other electro-magnet,  is  to  have  its  electro- 
magnetic functions  reduced  as  much  as  pos- 
sible, or  preferably  suppressed  altogether.  The 
field  is  to  be  very  strong. 

As  with  such  an  arrangement  there  is  no 
polar  effect  in  the  armature  except  that  due  to 
the  direct  magnetic  induction  of  the  field-mag- 
nets, it  follows  that  the  maximum  power  is  ob- 
tained with  any  given  current  when  the  brushes 
occupy  an  absolutely  neutral  position,  or,  in 
other  words,  when  there  is  no  "lead"  and  no 
distortion  or  rotation  of  the  field.  These  con- 
ditions do  away  with  the  most  troublesome  and 
prolific  cause  of  the  sparking  at  the  brushes. 

But  by  working  backward  in  this  way,  Mr. 
Mordey  saw  that  the  conditions  which  seemed 
to  be  best  for  a  motor  were  precisely  those 
which  the  would-be  designer  of  a  perfect 
dynamo  would  set  before  him  as  his  goal. 

Certain  perfect  analogies  had  been  arrived  at 
In  both  dynamos  and  motors,  according  to  this 
briefly  sketched  view:  (1.)  The  field  should 
be  a  very  strong,  the  armature  a  very  weak, 
electro  -  magnet.  (2.)  In  both  generators  and 
motors  "lead,"  distortion,  or  displacement  of 
brushes  or  of  magnetic  field  is  wrong,  and  is  to 
be  avoided  by  attention  to  (1).  Whatever 
"lead"  there  may  be  in  either  case,  there  is 
this  difference,  that  in  dynamos  this  "lead"  is 
in  the  direction  of  rotation;  in  motors  it  has  the 
opposite  direction,  as  the  course  of  the  current 
through  the  armature  is  reversed,  but  the  field 
is  the  same.  (3.)  In  both  generators  and  mo- 
tors absence  of  sparking  at  the  brushes  de- 
pends mainly  on  the  conditions  of  (1)  being 
complied  with.  (4.)  Reversal  of  rotation.  In 
neither  generators  nor  motors  is  movement  of 
the  brushes  necessary. 

But  having  got  so  far,  a  little  consideration 
suggested  the  probable  existence  of  another 
analogy.  Since  a  dynamo,  having  the  above 
theoretically  perfect  form  and  action,  with  a 
constant  field,  would  produce  a  constant  elec- 


6 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


tromotive  force  if  run  at  a  constant  speed,  in- 
dependently of  the  load  or  amount  of  current 
generated,  a  motor  constructed  on  the  same 
principles  and  having  a  constant  field,  if  sup- 
plied with  energy  at  a  constant  difference  of 
potential,  should  run  a.t  a  constant  speed,  inde- 
pendently of  load. 

If  this  should  prove  to  be  a  true  analogy,  a 
simple  means  of  obtaining  results  of  great  use 
in  the  practical  application  of  electricity  would 
be  obtained. 

The  experiments  were  carried  out  with  a 
"Victoria"  dynamo.  The  results  ultimately 
obtained,  which  are  given  in  the  following 
tabulated  account  of  the  experiments,  and  in 
the  curves  plotted  from  them,  show  that  this  fifth 
analogy  is  as  true  as  the  preceding  ones,  a  con- 
stancy of  speed  being  obtained  that  was  very 
remarkable,  even  when  the  load  was  increased, 
until  much  more  than  that  which,  as  a  genera- 
tor, was  usually  considered  the  full  working 
current  was  traversing  the  armature. 

Two  sets  of  readings  were  taken,  working 
up  to  about  the  same  current  in  each  set,  but 
with  the  potential-difference  of  the  supply 
different  in  the  two  cases,  as  stated.  The  field 
was  of  the  same  strength  throughout.  The 
load  consisted  of  another  "Victoria"  dynamo 
driven  through  a  modified  White's  transmis- 
sion-dynamometer, the  work  being  varied  as 
required  by  altering  the  external  circuit  of  this 
dynamo. 

At  first  it  appeared  that  the  counter-electro- 
motive force  of  the  motor  was  dependent  neither 
on  speed  nor  strength  of  field,  as  the  latter  was 
constant  and  the  former  very  nearly  so,  while 
the  current  rose  with  the  work;  but  calculation 
showed  that  this  was  not  the  case;  indeed,  it 
could  not  be  so. 

Calling  the  counter-electromotive  force  e,  and 
the  loss  of  potential  caused  by  the  resistance  of 
the  armature  e\,  and  the  difference  of  potential 
at  the  terminals  E,  then 

e  +  Cl  =  E. 

Calling  the  current  C,  and  the  resistance  of 
the  armature  R,  we  know  that 

«!  —  C  R. 

The  resistance  of  the  armature  of  the  motor 
in  question  was  .027  ohm,  which  we  call  .03  in 
order  to  make  some  allowance  for  the  effect  of 
heating. 


Experiments  with  a  D2  "  Victoria"  Shunt  Mo- 
tor at  Constant  E.  M.  F. 


Difference 

Speed. 

Current. 

of  potential 
at  termi- 

H. P.» 

nals. 

975 

36.3 

140 

1.8 

1          Curve  A. 

965 

66.5 

140 

6.6 

[Maximum    speed- 

948 

97.1 

140 

12.87 

j      variation  3  per 

945 

130.8 

140 

16.3 

J      cent. 

680 

29 

100 

1 

Curve  B. 

677 

61.4 

100 

4.8 

1  Maximum    speed- 

675 

102 

100 

9.14 

j      variation  3  per 

660 

125 

100 

11.7 

j      cent. 

•Including  an  unascertained  loss  in  transmission. 

In  the  first  and  last  readings  of  the  second 
set  of  tests  (curve  B)  Fig.  3,  we  have,  therefore, 
the  following  conditions: 


Now 


Speed. 

680 
660 


e,. 

.87 
3.75 

680  X  96.25 
660 


e. 
99.13 

96.25 


=99.13. 


From  which  it  appears  that  the  counter-elec- 
tromotive force  was  exactly  proportional  to  the 
speed,  as  is  to  be  expected  where  the  field  is 
constant  and  the  magnetic  distortion  nil. 

The  other  cases  do  not  work  out  with  the 
same  accuracy.  The  results  are,  however,  quite 
within  the  limits  of  error  inseparable  from  the 
rather  rough  conditions  of  workshop  tests. 

One  other  fact  may  be  pointed  out  in  connec- 
tion with  these  tables  of  results  and  curves.  In 
the  case  of  dynamos  working  with  a  constant 
field,  the  output  with  the  same  current  is  almost 
exactly  proportional  to  speed,  as  the  electro- 
motive force  is  also  simply  proportional  to 
speed.  So  with  the  motor,  the  speed  is  propor- 
tional to  the  electromotive  force  of  supply,  and 
the  work,  with  the  same  current  in  the  two 
cases,  is  simply  proportional  to  speed,therefore, 
to  electromotive  force. 

Turning  now  to  the  question  of  the  efficiency 
above  alluded  to,  in  order  to  localize  the  loss 
which  was  found  to  occur  in  motors  and  to  as- 
certain its  cause,  the  several  possible  sources  of 
waste  were  carefully  considered.  These  are: 
(a.)  Friction  at  the  bearing,  air  friction,  and 
friction  of  the  brushes  against  the  commutator. 
(6.)  Loss  of  energy  in  heating  the  armature 


ELEMENTARY  CONSIDERATIONS. 


and  field-conductors,  and  a  certain  loss  due  to 
self-induction,  (c.)  Loss  by  the  production  of 
eddy  currents  in  the  iron. 

Now  it  is  evident  especially  with  a  generator 
or  motor  having  the  qualities  sketched  above, 
that  at  the  same  speed,  and  working  with  the 
same  currents  in  its  conductors,  the  losses  un- 
der (a)  and  (b)  must  be  identical,  whether  it  be 
working  as  a  generator  or  as  a  motor.  And  as 
with  such  conditions  its  efficiency  as  a  motor 
is  lower  than  as  a  generator,  the  cause  of  the 
loss  must  be  sought  under  (c),  i.  e.,  the  eddy 
or  Foucault  currents  in  a  dynamo  must  be  less 
than  in  a  motor,  all  other  conditions  being 
the  same.  And  such  is  the  case,  the  explana- 
tion arrived  at  by  Mr.  Mordey  being  a  very 
simple  one. 

To  quote  again  from  Mr.  Mordey,  in  a  dyna- 
mo the  rotation  of  the  armature  causes  eddy 
currents  to  be  generated  in  the  iron  core,  in  the 
same  direction  as  in  the  conductor  proper  with 
which  the  core  is  surrounded.  Of  course,  as 
the  armature  is  always  more  or  less  subdivided  or 
laminated  in  a  direction  at  right  angles  to  the 
lines  of  force,  any  circulation  of  currents  round 
the  core  is  avoided,  but  local  currents,  which 
are  aptly  called  eddies,  are  set  up,  and,  taken 
as  a  whole,  these  eddy  currents  on  the  outside 
of  the  core  are  in  the  same  direction  as  the  cur- 
rent flowing  in  the  copper  conductors. 

In  an  electric  motor,  however,  the  eddy  cur- 
rents and  the  currents  in  the  copper  conductor 
are  in  opposite  directions;  as,  although  the  elec- 
tromotive force  set  up  in  the  conductor  is  in  the 
same  direction  in  a  motor  as  in  a  dynamo,  the 
current  in  the  former  is  forced  through  the 
armature  in  a  direction  contrary  to  the  electro- 
motive force,  or  opposite  to  its  course  in  a  gen- 
erator. According  to  the  laws  of  induction, 
therefore,  it  will  be  seen  that  while  in  a  dyna- 
mo the  two  sets  of  currents,  those  in  the  iron 


and  those  in  the  conductor,  tend  to  oppose  and 
reduce  one  another,  in  a  motor  they  act  in  such 
a  manner  as  to  mutually  assist  each  other. 
Thus,  with  the  strength  of  field,  the  current  in 
the  conductor,  and  the  speed,  the  same  in  the 
two  cases,  it  will  be  seen  that  in  a  motor  the 
eddy  currents  in  the  iron  core  of  the  armatures 
will  be  greater  than  in  a  generator,  and  there- 
fore the  heat  lost  in  the  former  will  be  more 
than  in  the  latter.  There  is  little  doubt  that 
this  is  the  cause  of  the  efficiency  of  motors 
being  lower  than  that  of  generators;  and  it 
points  to  the  advisability  of  giving  more  atten- 
tion in  the  former  to  those  principles  which  are 
well  understood  for  the  reduction  or  elimination 
of  eddy  currents. 

This  precaution  to  be  observed  was  first  point- 
ed out  by  Mr.  Mordey  but  had  been  recognized 
by  others,  and  is  of  the  greatest  importance. 
We  have  personally  seen  the  results  of  experi- 
ments upon  small  motors  which  with  solid  iron 
cores  gave  an  efficiency  of  only  20  per  cent,  but 
with  laminated  cores  were  brought  up  to  70  per 
cent,  efficiency. 

Regarding  the  difference  which  should  exist 
between  a  dynamo  and  a  motor,  Profs.  Ayrton 
and  Perry  have  advanced  the  theory,  that  in 
the  dynamo  the  field  magnets  should  be  large 
and  strong  and  the  armature  small  and  weak 
magnetically,  while  the  contrary  applies  in  the 
case  of  the  motor.  Practice,  however,  does 
not  bear  out  this  assumption,  for  only  recently 
Dr.  John  Hopkinson  in  some  tests  of  identical 
machines  of  his  design,  run  respectively  as 
dynamo  and  motor,  obtained  almost  identical 
efficiencies. 

We  may  conclude,  therefore,  that  there  is  no 
radical  difference  in  the  relative  actions  of  mo- 
tor and  dynamo  and  that  the  losses  which  have 
heretofore  been  experienced  were  due  to  faulti- 
ness  in  internal  construction. 


CHAPTBR   II. 


EARLY  MOTORS  AND  EXPERIMENTS  IN  EUROPE. 


THE  first  experiments  with  electric  motors  to 
attract  general  attention  throughout  Europe 
appear  to  have  been  those  of  Jacobi,  from  1834 
to  1838,  although  prior  to  that  time  the  field  had 
been  boldly  entered  by  other  acute  investiga- 
tors, who  sought  in  various  and  ingenious  ways 
to  utilize  the  principles  we  have  outlined  in 
the  preceding  chapter.  Thus  in  1826,  Barlow 
showed  how  to  employ  electricity  as  a  continu- 
ous motive  power  by  rotating  a  disc  of  copper 
between  the  poles  of  a  magnet.  The  current 
was  sent  perpendicularly  through  the  disc  from 
its  axis  to  circumference,  when  it  passed  into 
a  cup  of  mercury.  In  1830,  the  Abbe  Salvatore 
dal  Negro,  professor  of  natural  philosophy  at 
the  University  of  Padua,  made  a  motor  in 
which  a  permanent  magnet  oscillated  between 
the  legs  of  an  electro-magnet,  the  polarity  of 
the  limbs  changing  at  each  movement.  The 
oscillation  was  converted  into  continuous  rota- 
tion. 

In  1832,  before  the  Zurich  Society  of  En- 
gineers, Dr.  Schulthess  suggested  that  "  a  force 
such  as  we  obtain  by  interrupting  the  current 
and  establishing  it  again  could  be  advanta- 
geously applied  to  mechanics,"  and  in  1833  he 
exhibited  to  the  society  a  machine  in  which  his 
ideas  were  embodied.  About  this  time,  too, 
Botto  is  said  to  have  invented  a  motor  in  which 
a  lever  worked  like  that  of  a  metronome,  by 
the  alternate  action  of  two  fixed  electro-mag- 
netic cylinders  on  a  third  movable  cylinder 
attached  to  the  lower  arm  of  the  lever.  The 
upper  arm  imparted  a  continuous  circular 
movement  to  a  metal  fly-wheel. 

Thanks  to  the  substantial  aid  of  the  Emperor 
Nicholas  of  Russia,  who  contributed  a  sum  of 
$12,000  to  the  work,  Professor  Jacobi,  the  dis- 
coverer of  electro-plating,  was  enabled  to  prove 
in  1838,  at  St.  Petersburg,  on  the  Neva,  that  his 
electro  -  magnetic  motor  of  1834,  as  improved, 
could  replace  the  oarsmen  in  a  boat  carrying  a 
dozen  passengers.  Fig.  4  is  a  perspective  of 
the  Jacobi  motor  of  1834,  which  was  composed 


of  two  sets  of  electro-magnets.  One  set  was 
fastened  to  the  square  frame  T,  disposed  in  a 
circle  and  with  the  poles  projecting  parallel 
with  the  axis.  The  other  set  S  was  similarly 
fastened  to  the  disc  A  attached  to  the  shaft  and 
revolving  with  it.  Each  set  comprised  four 
magnets,  and  there  were  consequently  eight 
magnetic  poles.  The  current  from  a  powerful 
battery  passed  through  the  commutator  C  to  the 
coils  of  the  electro-magnets,  and  as  the  mag- 
nets attracted  each  other  the  disc  rotated.  By 
means  of  the  commutator  on  the  shaft,  the  cur- 
rent was  reversed  eight  times  during  each  revo- 
lution, just  as  the  poles  of  two  sets  of  magnets 
arrived  opposite  each  other.  Attraction  ceas- 
ing, repulsion  took  place,  and  the  motion  was 
thus  accelerated.  As  the  poles  were  alternately 
of  different  polarity,  the  reversals  had  the 
effect  of  causing  attraction  between  each  pole 
of  one  set  and  the  next  pole  of  the  other.  In 
his  historic  experiments  of  1838,  Jacobi  used  a 
modified  form  of  this  motor,  so  as  to  obtain 
greater  power.  In  the  new  form,  two  sets  of 
electro  -  magnets  were  attached  to  stationary 
vertical  frames,  one  on  each  side  of  a  rotating 
disc  or  star.  Each  set  was  composed  of  twelve 
electro -magnets.  The  electro-magnets  on  the 
rotating  star  were  made  in  the  form  of  bars 
passing  entirely  through  the  star.  The  axis 
carried  a  commutator  formed  of  four  wheels, 
regulating  the  direction  of  the  current  with  the 
result  that  when  the  straight  bar  magnets  were 
between  two  consecutive  poles  of  the  horse- 
shoe-magnets on  the  frames,  they  were  always 
attracted  towards  the  one  and  repelled  frojn 
the  other.  The  reversal  of  the  current  took 
place  when  the  rotating  poles  were  exactly 
opposite  the  fixed  ones.  The  boat  upon  which 
this  motor  .was  placed,  and  which  it  propelled 
by  means  of  paddles  on  the  Neva,  was  28  feet 
long,  7  feet  wide,  and  2  feet  9  inches  draught. 
No  fewer  than  14  passengers  were  carried.  The 
battery  power  was  furnished  by  320  Daniell 
cells,  the  weight  of  which  was  far  from  incon- 


EARLY  MOTORS  AND  EXPERIMENTS  IN  EUROPE. 


9 


siderable.  In  1839,  on  a  repetition  of  the  ex- 
periment, 138  Grove  cells  were  used.  At  no 
time  was  a  higher  speed  attained  than  3  miles 
per  hour. 

At  this  time,  1838-9,  an  inventive  Scotchman, 
named  Robert  Davidson,  had  built  a  lathe  and  a 
small  locomotive  for  which  electricity  was 
the  driving  power.  The  motor  for  the  locomo- 
tive consisted  of  two  cylinders  of  wood  fitted  to 


magnet.  By  this  arrangement,  it  followed  that 
the  current  was  interrupted  in  the  active  elec- 
tro-magnet and  sent  into  the  other,  its  vis-a-vis; 
and  thus  the  axle  was  continuously  turned. 
Acting  together,  the  four  sets  of  armatures  and 
the  two  axles  served  to  propel  the  car.  Two 
sets  of  cells  were  employed,  one  for  the  electro- 
magnets on  the  right  and  the  other  for  those  on 
the  left.  At  each  extreme  end  of  the  axles,  in- 


FIG.  4. — JACOB:  MOTOR. 


the  axles  of  four  wheels,  and  furnished  with 
four  sets  of  iron  armatures  arranged  to  pass 
between  the  poles  of  eight  electro-magnets. 
These  were  placed  horizontally  at  the  bottom 
of  the  car,  two  and  two,  by  their  opposite  poles, 
in  two  opposite  rows,  so  that  each  of  the  cylin- 
ders carried  two  sets  of  iron  bars  parallel  to  the 
axles.  The  bars  presented  themselves  succes- 
sively, as  the  cylinders  rotated,  to  the  poles  of 
the  corresponding  opposite  electro-magnets. 
When  one  of  the  bars  on  one  side  was  opposite 
its  magnet,  one  on  the  other  side  was  just 
within  range  of  the  attraction  of  its  electro- 


side  the  driving-wheels,  were  two  small  cylin- 
ders or  commutators  of  ivory  and  metal  upon 
which  bore  brushes  leading  the  current  from 
the  batteries.  Davidson's  car  was  16  feet  long, 
six  feet  broad,  and  of  five  tons  weight,  includ- 
ing batteries.  He  drove  it  at  a  speed  of  four 
miles  an  hour  with  40  cells  composed  of  plates 
of  iron  and  amalgamated  zinc  measuring  15 
inches  by  12. 

An  excellent  and  very  early  motor  was  that 
of  Elias,  made  at  Haarlem,  Holland,  in  1842.  It 
consisted  of  two  concentric  rings  of  soft  iron, 
the  inner  one  being  revolvable.  The  exterior, 


10 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


fixed  ring  supported  vertically,  had  six  enlarge- 
ments  dividing  it  into  six  equal    parts.     Be- 
tween the  dividing  pieces,  was  wound  insulated 
copper  wire,  and  the  winding  was  such  that  a 
current  entering  at  one  end  of  the  horizontal 
diameter  was  divided  between  the  upper  and 
lower  halves  of  the  ring,  and  left  at  the  other 
end  of  the  same  diameter.     The  interior  ring 
was  of    like   construction,   its  six 
poles  being  alternately  north  and 
south.      The   current   entered    by 
wires  with  each  of   which  three 
parts  of  the  commutator  were  in 
connection.  The  motor  was  worked 
by  two  batteries,  one  for  the  exter- 
ior ring  and  one  for  the  interior;  or 
by  a  slight  change  of  connections, 
one  battery  only  was  necessary.  In 
either  case,  the  alternate  north  and 
south  poles  of  the  exterior  ring  re- 
mained the  same.    The  poles  of  the 
inner  ring  changed  polarity  at  each 
sixth  of  a  turn,  the   commutator 
being  so  arranged  that  each  pole 
of   the    movable    ring    was    always    repelled 
by  one  of  the  fixed  poles  and  attracted  by  the 
other  and  next.     The  windings  of  the  two  rings 
were  very  close  together,  so  that  the  action  of 


illustrated  in  Fig.  5.  It  may  be  likened  to  a 
breast-wheel,  whose  paddles  are  acted  upon  by 
magnetism  instead  of  water.  The  wheels  were 
made  of  brass  or  other  non-magnetic  material, 
but  the  armature  bars  around  the  circumfer- 
ence were  of  soft  iron.  By  means  of  the  corn- 
mutating  device,  the  current,  cut  off  from 
each  electro-magnet  as  soon  as  the  armature 


FIG.  5. — FROMENT  MOTOR. 

parallel  currents  in  them  served  to  assist  in  the 
rotation  due  primarily  to  the  attraction  and  re- 
pulsion of  the  magnets. 

One  of   the  most  interesting  of   the    early 
motors  is  that  of  M.  Froment,  made  in  1845  and 


FIG.  6. — Du  MONCEI.  MOTOR. 

arrived  opposite  its  poles,  was  led  to  another 
magnet  until  the  said  armature  had  moved  on 
sufficiently  to  allow  the  next  armature  to  come 
within  range.  The  desired  effect  being  ob- 
tained, the  current  was  again  sent  through  the 
first  electro-magnet.  The  commutator  con- 
sisted of  spring  rollers  in  contact  with  each  of 
the  magnets  and  the  battery,  and  was  worked 
by  means  of  a  small  cam  on  the  driving  shaft. 
Froment  devised  other  ingenious  forms. 

In  1851,  Count  du  Moncel  devised  a  motor, 
Fig.  C,  not  unlike  that  of  Page,  and  of  which 
the  arrangement  reminds  one,  as  he  himself 
said,  of  an  oscillating  steam  engine.  The  iron 
cylinder,  which  in  the  position  of  the  crank  in 
the  figure,  has  passed  entirely  through  the  right- 
hand  bobbin  or  solenoid  and  passed  a  short  dis- 
tance into  the  other  bobbin,  is  shown  on  the 
point  of  being  attracted  into  the  latter.  On 
arriving  at  the  end  of  its  stroke,  it  was  within 
reach  of  an  iron  ring  or  disc,  terminating  the 
left-hand  bobbin.  This  gave  it  an  extra  im- 
petus that  carried  it  over  the  dead-point  corre- 
sponding to  the  movement  of  the  shaft  in  the 
opposite  direction.  Between  the  bobbins  was 
a  roller  upon  which  the  iron  rod  or  piston 
moved,  to  prevent  friction.  The  commutator 
was  composed  of  two  eccentrics  fixed  to  the 
axis  of  the  fly-wheel  and  insulated  from  each 


EARLY  MOTORS  AND  EXPERIMENTS  IN  EUROPE. 


11 


other.  A  fixed  silver  spring  in  connection  with 
each  one  of  the  bobbins  encountered  at  each 
half  revolution  of  the  fly-wheel  one  of  the 
eccentrics.  A  third  spring  large  enough  to 
bear  upon  both  of  the  eccentrics  brought  the 
current  to  the  two  latter  successively. 

The  Bourbouze  motor,  also  modeled  upon  that 
of  Professor  Page — described  in  Chapter  III.— 
was  made  like  a  steam  engine  with  two  pis- 
tons. This  early  type  is  shown  in  Fig.  7.  At 
the  two  extremities  of  the  horizontal  beam  were 
two  iron  cylinders  working  like  pistons  inside 
two  long  magnetizing  bobbins,  whose  lower 
ends  were  occupied  by  short  iron  cylinders 
joined  together  by  a  piece  of  iron  between  the 


FIG.  7. — BouRBorzK  MOTOR. 

bobbins;  constituting,  in  fact, an  electro-magnet. 
When  the  current  passed  into  one  of  the  bob- 
bins, the  corresponding  iron  rod  or  cylinder 
was  attracted  as  well  by  the  magnetic  pole  at 
its  end  as  by  the  coils,  and  it  was  drawn  down- 
ward until  the  current  was  cut  off  by  the  com- 
mutator. The  process  was  repeated  in  the 
other  bobbin,  and  the  beam  was  depressed  at 
the  corresponding  end.  This  to-and-fro  move- 
ment was  utilized  as  in  steam  engines  by  means 
of  a  crank  and  fly-wheel,  in  the  manner  indi- 
cated. The  commutator  was  a  plate  that  rubbed 
alternately  on  two  contacts  fixed  horizon- 
tally on  a  table,  and  was  set  in  motion  by  an 
eccentric  rod  worked  like  that  of  a  steam  engine. 
The  Bourbouze  motor  may  be  compared  to  an 
ordinary  working-beam  engine. 

Last,  though  not  least,  but  on  the  contrary  of 
epochal  importance,  comes  the  Pacinotti  motor 


invented  by  the  distinguished  Italian  physicist 
in  1861  and  described  by  him  in  II  Nuovo  Ci- 
mento  in  1864.  Pacinotti  builded  better  than  he 
knew,  and  it  was  not  until  1871  when  the  cele. 
brated  Gramme  dynamo  with  ring  armature 
made  its  appearance,  that  he  recognized  the 
true  value  of  his  motor  and  brought  it  from  its 
obscurity  and  oblivion  in  the  Philosophical  Mu- 
seum of  the  University  of  Pisa  to  be  seen  at 
the  exhibitions  of  Vienna  in  1873,  and  of  Paris 
in  1881.  Under  the  title:  "A  description  of  a 
Small  Electro-Magnetic  Machine,"  Dr.  Pacinotti 
said  :  "I  took  a  turned  iron  ring  furnished 
with  sixteen  equal  teeth.  This  ring  was  sus- 
pended by  four  brass  arms  B  B  (Fig.  8), 
which  fixed  it  to  the  axis  of  the  machine. 
Between  these  teeth  little  triangular  pieces  of 
wood  were  let  in,  wound  with  silk-covered 
copper  wire.  This  arrangement  was  to  obtain 
perfect  insulation  of  the  coils  or  bobbins  thus 
formed  between  the  iron  teeth.  In  all  the 
bobbins  the  wire  was  wound  in  the  same  direc- 
tion, and  each  was  formed  of  nine  turns.  Each 
is  thus  separated  from  the  other  by  an  iron 
tooth  and  the  triangular  piece  of  wood.  On 
leaving  one  bobbin  to  commence  the  next,  I  end 
the  wire  by  fixing  it  to  the  piece  of  wood  which 
separates  the  two  bobbins.  On  the  axle  carry- 
ing the  wheel  thus  constructed  I  grouped  all 
the  wires,  of  which  one  end  formed  the  end  of 
one  bobbin  and  the  other  the  commencement  of 
the  next,  passing  them  through  holes  for  this 
purpose  in  a  wooden  collar  fixed  on  this  same 
axle  and  then  attaching  them  to  a  commutator 
also  on  the  axle. 

"This  commutator  consisted  of  a  ring  or 
small  cylinder  of  wood,  having  on  its  circum- 
ference two  rows  of  grooves,  in  which  are  fitted 
sixteen  pieces  of  brass  (eight  in  each  row) ;  they 
are  placed  alternately,  and  concentric  with  the 
wooden  cylinder  on  which  they  form  a  spindle. 
Each  of  these  pieces  of  brass  is  soldered  to  the 
two  ends  of  wire  corresponding  with  two  con- 
secutive bobbins;  so  that  all  the  bobbins  are  con- 
nected, each  being  joined  to  the  following  by  a 
conductor,  of  which  one  of  the  pieces  of  brass 
of  the  commutator  forms  a  part.  If  we  put  two 
of  these  pieces  of  brass  in  communication  with 
the  poles  of  a  battery  by  means  of  two  metallic 
rollers,  O,  the  current,  in  dividing,  will  go 
through  the  coil  at  both  points  where  the  ends 
of  the  wire  fastened  to  the  pieces  of  brass  com- 
municate with  the  rollers ;  and  magnetic  poles 


12 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


will  appear  in  the  iron  circle  in  the  diameter 
perpendicular  to  A  A.  On  these  poles  acts  a 
fixed  electro-magnet,  which  determines  the  ro- 
tation of  the  circular  electro-magnet ;  the  poles 
of  the  circular  electro-magnet  when  in  movement 
always  appearing  in  the  fixed  positions  corres- 
ponding to  the  communication  with  the  battery." 
He  said  further: — "  It  seems  to  me  that  what 
increases  the  value  of  this  model  is  its  faculty 
for  being  transformed  from  electro-magnetic 
into  magneto-electric  with  continuous  current. 


permanent  magnet;  the  electro-magnetic  ma- 
chine resulting  from  this  will  have  the  advan- 
tage of  giving  additional  induced  currents  all 
in  the  same  direction,  without  necessitating  the 
use  of  mechanism  to  separate  the  opposite  cur- 
rents or  make  them  converge."  As  to  reversi- 
bility, he  remarked  with  keen  foresight: — "  This 
model  further  shows  how  the  electro-magnetic 
machine  is  the  complement  of  the  magneto-elec- 
tric machine,  for,  in  the  first,  the  current  ob- 
tained from  any  source  of  electricity  circulating 


FIG.  8. — THE  PACINOTTI  MACHINE. 


If,  instead  of  the  electro-magnet,  there  was  a 
permanent  magnet,  and  the  circular  magnet 
was  made  to  turn,  we  should  have,  in  fact,  a 
magneto-electric  machine  which  would  give  a 
continuous  induced  current  always  in  the  same 
direction.  To  develop  an  induced  current  by 
the  machine  thus  constructed,  I  brought  to  the 
magnetic  wheel  the  opposite  poles  of  two  per- 
manent magnets,  or  I  magnetized  by  means  of 
a  current  the  fixed  electro-magnet,  and  I  made 
the  circular  electro-magnet  to  turn  on  its  axis. 
In  both  cases  I  obtained  an  induced  current  al- 
ways in  the  same  direction.  It  will  easily  be  seen 
that  the  second  method  is  not  practicable,  but 
that  an  electro-magnet  is  easily  replaced  by  a 


in  the  bobbins  produces  movement  of  the  wheel 
with  its  consequent  mechanical  work;  whilst  in 
the  second,  mechanical  work  is  employed  to 
turn  the  wheel,  and  obtain,  by  the  action  of  the 
permanent  magnet,  a  current  which  may  be 
transmitted  by  conductors  to  any  required 
point." 

Other  early  European  experimenters  of  merit 
might  be  mentioned,  such  as  Wheatstone,Mc- 
Gawley,  Gaiffe,  Larmenjeat,  Roux,  and  Hjorth. 
but  the  descriptions  above  will  serve  to  show  the 
state  of  the  art  as  regards  electric  motors  down 
to  the  time  when  the  reversibility  of  the  dyna- 
mo-electric machine  gave  an  entirely  new  direc- 
tion to  the  efforts  of  inventive  genius  in  Europe. 


CHAPTKR   III. 


MOTORS  AND  EXPERIMENTS  IN  AMERICA. 


As  all  previous  works  dealing  in  any  way  with 
electric  motors  have  little  to  say  about  Amer- 
ican work  in  the  field,  no  apology  need  be 
offered  for  the  effort  made  in  this  chapter  to 
supply,  in  part,  the  deficiency. 

The  first  electric  motor  patented  in  this  coun- 
try was  constructed  early  in  1837,  and  was  the 
device  of  Thomas  Davenport,  a  blacksmith, 
of  Brandon,  Vt.,  who  styled  his  invention  an 
"Application  of  Magnetism  and  Electro-Mag- 
netism to  Propelling  Machinery."  The  frame 
of  the  machine  was  made  of  a  circular  ring  and 
disc,  horizontally  arranged,  the  former  being 
supported  upon  the  latter  by  vertical  posts. 
Upon  the  lower  disc  were  mounted  two  copper 


FIG.  9. — DAVENPORT  MOTOR. 

segments,  arranged  in  the  centre,  as  seen  in  the 
sectional  view,  which,  together,  constituted  a 
circular  ring  pole-changer.  The  electro-mag- 
nets were  four  in  number  and  projected  hori- 
zontally in  radial  lines  from  a  common  centre, 
Fig.  9.  Through  this  centre  passed  a  vertical 
shaft  having  bearings  in  the  frames  so  as  to 
have  a  revolving  motion.  The  conducting  wires 
from  the  source  of  energy  extended  up  from  the 
copper  segments  parallel  with  the  shaft  of  the 
electro-magnet.  Davenport  arranged  within  the 
inner  periphery  of  the  upper  horizontal  ring  a 
ring  of  steel  cut  in  two,  forming  a  pair  of  steel 
segments,  which  he  termed  "  artificial  mag- 
nets." The  description  of  this  device  in  the 
patent  specification  is  somewhat  obscure,  but 
the  inference  is  that  these  were  permanent 


magnets,  and  being  semi-circular  in  shape,  they 
approximated  the  form  of  a  horseshoe.  The 
principle  of  operation  of  this  machine  will  be 
apparent  at  a  glance.  The  polarity  of  the  elec- 
tro-magnets was  changed  during  their  revolu- 
tion by  the  wiping  contact  of  their  connections 
with  the  two  segmental  plates  on  the  bottom 
disc,  these  segments  connecting  with  the  posi- 
tive and  negative  poles  of  the  battery. 

As  a  remarkable  instance  of  the  granting  of 
a  broad  claim  by  the  Patent  Office  to  an  in- 
ventor, that  of  Davenport  may  be  cited.  It 
reads: — "Applying  magnetic  and  electro-mag- 
netic power  as  a  moving  principle  for  machin- 
ery in  the  manner  above  described,  or  in  any 
other  substantially  the  same  principle." 

To  Davenport  appears  to  belong  the  honor 
of  first  printing  by  electricity  as  well  as  of  first 
building  an  electric  railway.  A  paper  called 
The  Electro- Magnet  and  Mechanics'  Intelligencer 
was  published  by  him  in  1840.  It  is  said  that 
he  obtained  the  current  for  his  machine  from  a 
battery  of  amalgamated  zinc  and  sheets  of  plat- 
inized silver.  Pieces  of  sheet  iron  platinized 
might,  he  thought,  be  used  with  advantage 
instead  of  the  silver  plates.  The  electrodes 
were  plunged  into  water  acidulated  with  sul- 
phuric acid  in  the  proportion  of  nine  parts  of 
water  to  one  of  acid.  Davenport  and  Ransom 
Cook  are  said  by  Prof.  Moses  G.  Farmer  to 
have  used  in  1840,  with  motors,  a  zinc  and  cop- 
per battery,  with  a  solution  of  blue  vitriol  as 
the  exciting  fluid. 

Davenport  was  a  man  far  ahead  of  his  time. 
Having  seen  a  magnet  in  use  at  Crown  Point, 
on  Lake  Champlain,  in  1833,  extracting  iron 
from  pulverized  ore,  he  jumped  at  once  to  the 
idea  that  he  could  apply  magnetism  to  the  pro- 
pulsion of  machinery.  He  bought  the  magnet, 
began  to  experiment,  and  by  1834  had  obtained 
rotary  motion.  He  then  went  to  Washington, 
where  he  took  steps  to  obtain  the  patent  above 
mentioned,  and  in  the  autumn  of  1835  he  set  up 
a  small  circular  railway  at  Springfield,  Mass., 


14 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


over  which  he  ran  an  electro-magnetic  engine. 
In  December  of  the  same  year  he  exhibited  his 
road  in  Boston  for  tw,o  weeks.  During  1837  he 
showed  to  Prof.  Benjamin  Silliman,  in  New 
York,  a  motor  in  which  "the  exterior  fixed 
circle  is  now  composed  entirely  of  electro-mag- 
nets. The  conducting  wires  were  so  arranged 
that  the  same  current  that  charged  the  magnets 
of  the  motive  wheel  charged  the  stationary 
ones  placed  around  it,  only  one  battery  being 
used.  It  lifted  sixteen  pounds  very  rapidly, 
and  when  the  weight  was  removed,  it  performed 
more  than  six  hundred  revolutions  per  minute." 

In  June,  1838,  Nelson  Walkly,  of  Tuscaloosa, 
Ala.,  devised  an  electric  motor,  the  principal 
improvement  being  in  the  mode  of  changing 
the  poles  of  the  electro-magnets. 

The  electro-magnets  employed  by  Walkly 
were  semi-circular  in  form.  Two  of  them  were 
fixed  to  a  horizontally  -  revolving  wheel  with 
proper  insulations.  The  ends  of  the  wires  on  the 
revolving  magnets  were  connected  with  two 
segmental  collars  placed  on  the  vertical  shaft. 
These  collars  were  placed,  one  above  the  other, 
on  the  shaft,  but  insulated  therefrom.  The  cur- 
rents of  the  two  revolving  magnets  were  taken 
off  by  wiping  electrodes  arranged  to  lie  against 
the  collars  which  led  to  the  negative  and  posi- 
tive elements  of  the  battery;  Fig.  10. 


was  made  to  vibrate  by  means'  of  a  double 
elliptic  cam  fixed  on  the  upper  end  of  the  verti- 
cal shaft  by  means  of  a  connecting  pitman. 
Should  more  revolving  magnets  be  used  than 
two,  the  cam  might  be  fixed  on  a  pinion,  re- 
volving more  times  than  the  main  shaft,  so  as 


FIG.  10.— WALKLY  MOTOR. 

Through  a  post  fixed  in  the  right-hand  side  of 
the  upper  platform,  Fig.  11,  were  fixed  two 
conductors  connected  with  the  battery.  The 
outer  ends  of  these  spring  conductors,  when  at 
rest,  pressed  against  an  insulated  pin,  and  be- 
tween their  ends  was  interposed  a  lever,  the 
end  of  which  was  just  the  size  of  the  insulated 
pin.  This  lever  was  composed  of  two  plates  of 
metal  with  a  piece  of  wood  between  them,  and 


FIG.  11. — WALKLY  MOTOR. 

to  change  the  polarity  every  time  one  of  the 
rotary  magnets  came  opposite  one  of  the  sta- 
tionary ones. 

To  magnetize  the  outer,  or  stationary,  mag- 
nets, the  current  of  electricity  passed  from  the 
positive  side  of  the  battery  to  the  conductor, 
and  thence  to  the  lower  plate  of  the  vibrating 
lever,  and  so  to  one  of  the  stationary  mag- 
nets. When  the  machine  was  at  rest,  the  lever 
would  be  in  contact  with  the  spring  conductors, 
and  the  ends  of  the  rotary  magnets  opposite  the 
ends  of  the  stationary  ones.  By  moving  the 
rotary  magnets  the  cam  would  move  the  end  of 
the  lever  and  the  end  of  the  spring  away  from 
the  insulated  pin,  leaving  the  opposite  spring 
resting  against  the  pin.  The  north  poles  of  the 
stationary  and  rotary  magnets  would  then  repel 
each  other,  causing  the  latter  to  revolve,  so  that 
the  lever  was  vibrated  back,  thereby  moving 
the  spring  on  the  opposite  side  and  changing 
the  polarity  of  the  stationary  magnets,  and 
so  on. 

The  next  American  patent  for  an  electrical 
motor,  in  chronological  order,  appears  to  be 
that  granted  to  Solomon  Stimpson,  September 
12,  1838,  Figs.  12  and  13.  Between  two  vertical 
circular  brass  rings  were  attached  the  poles 
of  a  series  of  stationary  magnets  by  screws. 
Within  or  between  the  stationary  magnets  were 
a  series  of  revolving  ones  mounted  upon  a 


EARLY  MOTORS  AND   EXPERIMENTS  IN  AMERICA. 


15 


central  shaft,  the  whole  number  of  magnets — 
both  stationary  and  revolving — being  twelve. 
The  wires  of  all  the  stationary  electro-magnets 
were  connected  terminally  with  mercury-hold- 
ing cells  resting  on  the  base  plate.  These  insu- 


1 


FIG.  12. — STIMPSON  MOTOR. 

lated  cells,  the  inventor  explained,  were  for 
battery  communications.  The  electric  connec- 
tions of  the  revolving  magnets  passed  out  at 
one  side  and  were  connected  with  a  pole- 
changer. 

The  galvanic  current  was  not  distributed  to 
the  revolving  magnets  individually,  but  they 
were  charged  by  pairs,  the  magnets  of  each 


FIG.  13. — STIMPSOX  MOTOR. 

being  charged  in  sequence.  Wiping  springs 
connected  with  the  conducting  wires  were 
arranged  to  lie  against  the  revolving  pole- 
changer,  which  was  composed  of  a  series  of 
metallic  segments  with  interposing  insulating 
material.  The  wiping  contact  was  made  upon 
the  opposite  sides  of  the  pole-changer,  and  thus 


were  constituted  two  permanent  battery  poles. 
As  the  machine  revolved,  the  two  opposite  ex- 
tremities of  the  wires  were  presented  in  alter- 
nate order  to  the  same  battery  pole,  and  thus  a 
change  of  polarity  was  effected.  Power  was 
applied  through  a  pinion  on  the  shaft  com- 
mencing with  the  cog  gear. 

The  patent  of  Truman  Cook,  of  New  York, 
was  granted  in  1840.  The  body  of  the  rotating 
armature,  Fig.  14,  was  made  of  wood,  brass, 
or  any  other  material  not  affected  by  magnetic 
influence.  Upon  the  periphery  of  this  arma- 
ture were  placed  six  rectangular  bars  of  soft 
iron,  at  equal  distances  apart,  and  extending 
from  end  to  end  parallel  with  tne  axis.  The 
electro-magnets  were  of  the  usual  horseshoe 


FIG.  14. — COOK  MOTOR. 


form,  and  were  placed  in  pairs,  so  that  the 
opposite  poles  of  each  of  them,  at  the  same 
instant,  stood  immediately  over  the  ends  of  the 
two  contiguous  armatures  or  keepers.  In  this 
machine  there  were  three  pairs  of  electro- 
magnets. 

There  were  two  mercury  cups  located  in  the 
frame  in  which  the  ends  of  the  electro-magnet 
coils  terminated,  those  wires  which  formed  one 
termination  passing  into  one  cup,  and  those 
forming  the  opposite  electric  pole  passing  into 
the  other  mercury  cup.  A  cam  wheel  secured 
to  the  armature  shaft  was  made  to  touch  the 
terminal  wires  from  one  electric  pole,  so  that  the 
ends  of  the  wire  were  lifted  from  the  mercury 
cup  at  each  rotation. 

The  notches  shown  in  this  cam  wheel  corre- 
sponded with  the  number  of  the  revolving 
armatures,  and  were  so  arranged  as  to  sus- 


16 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


pend  the  transmission  of  the  current,  and,  con- 
sequently, the  magnetic  induction  at  the  proper 
moment  for  allowing  the  armatures  to  pass  the 
magnets.  One  of  the  projecting  teeth  on  the 
cam  was  insulated,  and  it  was  this  one  that 
raised  the  terminal  wires  of  one  electric  pole  by 
the  action  of  the  cam.  In  the  drawings  these 
wires  are  not  represented  as  dipping  into  the 
mercury  cup,  but  as  resting  upon  a  piece  of 
metal  which  forms  a  conducting  communica- 
tion with  the  cup. 


--_  • 

{gr---- 

1    \ 

1  1       R 

n 

•••      •  , 

Jl  / 

r.---3--:_-------.-. 

U       U 

O— 


FIG.  15. —  I, ii  i  ii    MOTOK. 

The  length  of  the  several  armatures  was  less 
than  that  of  their  distance  from  each  other,  and 
the  north  and  south  poles  of  the  magnets,  con- 
stituting each  pair,  were  at  a  distance  apart 
corresponding  to  the  distance  of  the  armatures. 
The  influence  of  the  magnetic  field  was  conse- 
quently exerted  between  the  opposite  poles  of 
the  magnets  constituting  the  pair,  this  resulting 
from  their  proximity  being  greater  than  that  of 
the  opposite  poles  of  each  individual  magnet. 


FIG    16. — LILLIE  MOTOR. 

It  will  be  perceived  that  these  magnets  oper- 
ated in  pairs,  one  of  thehi  extending  its  influ- 
ence directly  to  the  other,  thus  mutually  actu- 
ating the  armatures  as  they  approached.  Mr. 
Cook  showed  a  modified  form  of  armature  in 
the  detail  view,  which  consisted  of  several 
plates  of  soft  sheet  iron,  placed  side  by  side, 
with  narrow  sheets  of  copper  interposed  be- 
tween them  at  each  end. 

In  1850,  John  H.   Lillie,  of  Joliet,  111.,  con- 
structed an  electric  motor  comprising  a  series 


of  radially  arranged  permanent  horseshoe  mag- 
nets, revolving  on  a  wheel  in  proximity  to  sta- 
tionary electro-magnets,  Figs.  15  and  1(>.  A 
helix  of  fine  wire  was  wound  around  the  outside 
of  the  electro-magnet,  "  for  the  double  pur- 
pose," he  said,  "of  producing  other  electro- 
magnets, and  to  destroy  the  secondary  or  vibra- 
tory currents  in  my  first  electro-magnet." 

On  one  end  of  the  axis  of  the  wheel  to 
which  the  permanent  magnets  were  attached 
was  a  large  spur-wheel,  which  drove  two  pin- 
ions to  which  the  commutator  was  attached. 
The  frame  of  the  machine  received  two  station- 
ary electro-magnets  on  a  line  radial  from  the 
shaft,  one  on  each  side.  Around  the  usual  coils 
of  the  electro-magnets  were  wound  secondary 
coils  which  were  connected  with  the  electro- 


FIG.  17.— XKFF  MOTOR. 

magnets  placed  below  the  bed -plate  of  the 
frame,  where  they  formed  a  circuit  and  caused 
the  latter  magnets  to  be  energized.  Secondary 
currents  were  said  to  be  destroyed  in  this  way. 
The  lower  magnets  were  so  placed  as  to  aid  in 
the  propulsion  of  the  wheel.  Mr.  Lillie  found 
it  necessary  to  have  the  permanent  magnets 
quite  long,  otherwise  their  poles  would  be 
changed  by  a  powerful  current  in  the  electro- 
magnet. 

Jacob  Neff,  of  Philadelphia,  devised  an  elec- 
tric motor  in  1851,  Figs.  17  and  18.  The  metal 
frame  of  the  Neff  electric  motor  was  connected 
by  cross-bars,  to  which  the  armatures  were 
attached  in  such  a  manner  that  each  magnet 
had  a  separate  armature.  The  rotating  wheel  of 
electro-magnets  was  secured  by  means  of  insu- 
lated nuts  in  the  wheel  -  frame,  which  was 
tapped  for  the  purpose  of  receiving  the  magnets. 


EARLY  MOTORS  AND   EXPERIMENTS   IN  AMERICA. 


17 


The  commutator  was  composed  of  three  sep- 
arate discs.  The  outside  ones  had  flanges,  by 
means  of  which  they  were  secured  to  the  shaft, 
and  they  were  also  adjusted,  as  circumstances 
might  require,  by  means  of  set  screws,  non- 
conducting substances  being  placed  between  the 
discs.  Each  disc  had  sixteen  platinum  points 
on  its  periphery,  corresponding  in  number  to 
the  armatures.  Friction  rollers  covered  with 
platinum  were  arranged  to  work  under  the  com- 
mutators, they  being  retained  in  their  position 
by  set  screws  above  their  journals  and  spiral 
springs  beneath.  The  commutators  completed 
the  circuit  when  the  battery  was  connected, 
and  the  magnets  were  energized  as  they  came 
in  contact  with  the  friction  rollers  and  demag- 


NKFF  MOTOR. 


netized  as  they  left  it.  As  will  be  understood, 
the  magnets  were  energized  when  their  edge 
was  near  the  edge  of  the  armatures,  and  con- 
tinued attracting  until  the  magnets  were  imme- 
diately under  or  opposite  to  the  armatures. 
The  connection  was  then  broken  and  the  mag- 
nets passed  freely  under  the  armatures. 

Another  interesting  early  motor  patented 
about  this  time  was  that  of  Thomas  C.  Avery, 
of  New  York,  Figs.  19  and  20.  In  this  electro- 
magnetic engine,  Avery  combined  a  series  of 
electro-magnets  in  pairs  so  as  to  present  their 
poles  toward  a  common  centre,  sufficient  space 
being  provided  between  the  poles  of  the  mag- 
nets for  an  intervening  axis.  This  axis  con- 
sisted of  revolving  sets  of  bars  extending 
radially  outward  and  passing  between  the  poles 
of  the  magnets.  At  the  points  where  the  ends 
of  the  magnets  approached  the  axis,  pieces  of 
brass  or  other  non-magnetic  material  were  in- 
terposed to  prevent  the  ends  of  the  magnets 


acting  upon  the  axis.  On  each  side  of  these 
collars  of  brass,  at  a  sufficient  distance  apart, 
were  arranged  on  the  axis  a  series  of  arms  be- 
tween each  two  of  which  the  legs  of  the  magnet 
were  allowed  to  pass,  and  on  which  they  exer- 
cised their  attractive  force  alternately  as  the 


FIG.  19. — AVKKY  MOTOR. 

circuit  was  made  and  broken  through  the  oppo- 
site pairs  of  electro-magnets.  Two  cams  were 
attached  to  the  rotating  axis  for  the  purpose  of 
breaking  and  changing  the  direction  of  the 
electric  current  from  the  vertical  to  the  hori- 
zontal magnets  continuously.  Two  circuit 
closers  acted  at  their  outer  ends  on  these  cams 
by  means  of  compression  springs,  ami  were 


FIG.  20. — AVERY  MOTOR. 

attached  at  their  back  ends  by  a  screw  to  sup- 
port pieces  fixed  to  the  side  of  the  frame. 
These  support  pieces  were  attached  to  a  cross- 
bar, and  were  in  contact  with  conducting  ma- 
terial secured  to  the  under  side  of  the  cross-bar 
for  the  purpose  of  reversing  the  direction  of 
the  electric  currents. 


18 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


In  1852,  John  S.  Gustin,  of  Trenton,  N.  J., 
constructed  an  electric  motor  arranged  for  oper- 
ating a  pump.  A  side  and  an  end  elevation, 
Figs.  21  and  22,  are  here  given.  In  connec- 
tion with  the  oscillating  beam  shown  was  a 
pendulum  arm  extending  downward  and  carry- 


FIG.  21. — GUSTIN  MOTOR. 


ing  a  weighted  ball.  At  the  lower  extremity 
of  this  pendulum  was  a  projection  which  moved 
the  valve,-  alternating  the  battery  current  on 
the  magnets  by  the  vibrating  motion  of  the 
pendulum.  The  pendulum  was  intended  to 
move  between  two  spring-buffers  at  either  end 
of  its  throw,  which  were  designed  to  relieve 
the  force  of  the  blow  of  the  pendulum,  and  also 
to  assist  in  reversing  its  motion.  On  the  valve 
or  break-piece  was  a  conducting  plate,  its 
length  so  adjusted  that  it  could  form  a  con- 
nection with  but  one  side  at  the  same  time. 
The  negative  wires  from  the  helices  were  both 
led  to  a  like  strip  of  copper  on  the  opposite  side 
of  the  bed-plate.  At  either  end  of  the  oscil- 
lating beam  were  pivoted  links  which  connected 
or  suspended  the  armatures  of  the  magnets. 
The  arrangement  of  the  pump  is  shown  at  one 
side  of  the  device,  its  piston-rod  being  con- 
nected with  one  end  of  the  working-beam.  At 
the  opposite  end  of  the  beam  was  a  long  de- 
pending link  which  was  pivoted  at  its  lower 
end  to  a  regulating  spring.  One  end  of  this 
spring  was  securely  fixed  in  the  frame. 

A  thin  piece  of  rubber  cloth  was  placed  on 
the  magnet  poles  to  prevent  the  adhesion  of 
the  armature  to  the  magnets  when  the  battery 
current  was  broken,  and  also  to  prevent  vio- 
lent concussion  of  contact.  The  regulating 


spring  was  adjusted  in  its  tension  in  this  ma- 
chine so  as  to  require  twenty  pounds  force  to 
move  it  one  inch  to  the  point  of  extension 
(shown  by  dotted  lines)  with  the  rod  from  the 
working-beam,  and  so  set  as  to  be  at  rest  when 
the  pendulum  was  central.  The  object  of  the 
regulating  spring  was  to  receive  the  excess  of 
power  of  the  electro-magnets  when  they  were 
closing  and  to  give  it  off  when  they  were  too 
far  extended  for  the  attractive  force  to  be 
available.  With  the  assistance  of  the  pendu- 
lum and  this  spring,  nearly  an  equal  force  was 
said  to  be  exerted  throughout  the  stroke  of  the 
pump.  Gustin  stated  that  the  tension  of  this 
regulating  spring  should  be  fully  equal  to  the 
power  required  to  move  the  pump  when  the 
spring  was  at  its  extreme  point  of  action.  At 
that  point  the  electro-magnets  of  the  Gustin 
motor  were  so  feeble  that  the  spring  had  nearly 
the  whole  work  to  perform. 


w  u 

FIG.  22. — GUSTIN  MOTOR. 


In  the  same  year  Gustin  devised  another 
electro-magnetic  motor.  The  legs  of  the  mag- 
nets of  this  motor  were  nine  inches  long  and 
cylindrical;  the  armatures  were  of  the  same 
length  and  form,  and  were  adapted  to  move 
longitudinally  in  the  helices  which  projected 
beyond  the  poles  of  the  magnet  forming  a  hol- 
low core.  Five  magnets  were  employed  and 


EARLY  MOTORS  AND   EXPERIMENTS  IN  AMERICA. 


19 


ten  armatures,  there  being  an  armature  to  each 
pole  of  the  magnets.  Adjusting  nul£  were  em- 
ployed to  secure  the  armatures  in  different 
relative  positions  on  their  supporting  rods. 

The  armatures  of  one  magnet  of  the  series 
were  arrange  1  to  allow  of  a  play  of  one  inch, 
the  armatures  of  the  next  magnet  having  a 
play  of  two  inches,  and  so  on.  At  the  energiza- 
tion of  the  series,the  magnet  whose  armatures 
had  the  play  of  one  inch  was  the  most  power- 
fully attracted,  whereupon  the  current  was 
broken  on  that  magnet  and  and  closed  upon  the 
next  magnet  of  the  series.  A  like  result  was 
produced  successively  upon  all  the  magnets  of 
the  series  until  they  had  all  performed  their 
work.  The  stroke  of  the  working-beam  was 
not  yet  complete,  however,  when  the  fifth  pair 
of  magnets  closed.  One  series  of  magnets 


a  piston-rod  connected  to  the  crank  of  a  shaft 
carrying  a  fly-wheel.  The  core  moved  down- 
ward by  its  weight  until  its  upper  end  was  just 
leaving  the  solenoid,  and  thus  one  movement 
of  the  piston  was  accomplished.  On  passing 
the  current  the  core  or  piston  was  attracted  up- 
ward, and  thus  the  second  movement  was  com- 
pleted. A  commutating  device  was  attached 
to  the  shaft  which  automatically  admitted  the 
current  into  the  coil  and  cut  it  off  at  the  right 
moment. 

Professor  Page  soon  improved  on  this  single- 
acting  electric  engine  by  adding  another 
solenoid,  which  could  pull  the  piston  in  the 
other  direction  without  the  assistance  of  gravity. 
Fig.  23  shows  this  form  of  engine  which  takes 
electricity  at  both  ends  of  the  "cylinder,"  to 
borrow  the  expression  of  steam  engineers.  This 


FIG.  23. — PAGE  MOTOR. 


having  performed  their  work,  the  other  series, 
working  in  connection  with  the  opposite  end  of 
the  working-beam,  were  in  readiness  to  perform 
their  work  in  like  manner.  The  motion  of  the 
working-beams  was  communicated  through 
their  bearing-rods  to  the  crank  and  fly-wheel, 
thereby  producing  rotary  motion. 

The  most  celebrated  early  motor  next  to  that 
of  Jacobi  was  undoubtedly  that  of  Prof.  C.  G. 
Page,  of  the  Smithsonian  Institute.  This  de- 
pended upon  a  different  principle  from  that  of 
the  others.  When  the  end  of  a  bar  of  iron  was 
held  near  a  hollow  electro-magnetic  coil  or  sole- 
noid, the  iron  bar  was  attracted  into  the  coil  by 
a  kind  of  a  sucking  action  until  the  bar  had 
passed  half  way  through  the  coil,  after  which 
no  further  motion  took  place.  Professor  Page 
constructed  an  electric  engine  on  this  principle 
about  1850.  The  solenoid  was  placed  vertically, 
like  the  cylinder  of  an  upright  engine.  A  rod 
of  iron,  by  way  of  armature,  was  fastened  to 


arrangement  will  be  readily  understood.  There 
are  two  solenoids  and  each  has  its  iron  rod  pass- 
ing through  it,  though  they  are  joined  into  one 
piston  by  a  piece  of  non-magnetic  material. 
The  piston  is  attached  to  a  frame  /  / '  which 
slides  through  supports,  and  in  this  way  it  is 
free  to  move  inside  the  solenoids.  The  current 
is  sent  alternately  through  each  coil  by  an  ec- 
centric disc  on  the  axle  (which  suggests  a 
further  resemblance  of  this  motor  to  a  steam- 
engine).  This  eccentric  touches  first  one  and 
then  the  other  of  two  springs  e  e,  connected  to 
the  solenoids. 

A  large  motor  of  this  description  was  con- 
structed by  Professor  Page,  in  1850,  which  de- 
veloped over  ten  horse-power.  Professor  Page 
sought  to  apply  his  motor  to  locomotion,  and 
he  actually  constructed  an  electric  locomotive 
to  demonstrate  the  practicality  of  his  scheme. 
But  he  never  achieved  much  success,  as  might 
have  been  foreseen.  Among  the  improvements 


20 


THE  ELECTRIC   MOTOR  AND   ITS   APPLICATIONS. 


which  Professor  Page  introduced  was  that  of 
making  each  solenoid  double,  so  that  the  arms 
of  a  U  magnet  could  slip  into  them,  instead 
of  one  single  bar.  As  the  solenoids  attracted 
most  strongly  when  the  cores  were  almost  out 
of  them,  he  wound  his  solenoids  in  short  sec- 
tions, and  a  sliding  commutator  worked  by  the 
motion  of  the  cores  successively  cut  out  the  sec- 
tions of  coil  which  the  cores  had  entered  and 
transferred  the  current  to  others  ahead  of  them, 
and  thus  the  range  of  attraction  was  greatly  in- 
creased. 

Professor  Page,  it  is  interesting  now  to  recall, 
made  the  trial  trip  with-  his  electro-magnetic 
locomotive  on  Tuesday,  April  29,  1851,  starting 
from  Washington,  along  the  track  of  the  Wash- 
ington &  Baltimore  Railroad.  His  locomotive 
was  of  sixteen  horse-power,  employing  100  cells 
of  Grove  nitric  acid  battery,  each  having  plat- 
inum plates  eleven  inches  square.  The  progress 
of  the  locomotive  was  at  first  so  slow  that  a  boy 
was  enabled  to  keep  pace  with  it  for  several 
hundred  feet.  But  the  speed  was  soon  increased, 
and  Bladensburg,  a  distance  of  about  five  miles 
and  a  quarter,  was  reached,  it  is  said,  in  thirty- 
nine  minutes.  When  within  two  miles  of  that 
place,  the  locomotive  began  to  run,  on  nearly  a 
level  plane,  at  the  rate  of  nineteen  miles  an 
hour,  or  seven  miles  faster  than  the  greatest 
speed  theretofore  attained.  This  velocity  was 
continued  for  a  mile,  when  one  of  the  cells 
cracked  entirely  open,  which  caused  the  acids 
to  intermix,  and,  as  a  consequence,  the  propell- 
ing power  was  partially  weakened.  Two  of  the 
other  cells  subsequently  met  with  a  similar  dis- 
aster. The  professor  proceeded  cautiously,  fear- 
ing obstructions  on  the  way,  such  as  the  coming 
of  cars  in  the  opposite  direction,  and  cattle  on 
the  road.  Seven  halts  were  made,  occupying 
in  all  forty  minutes.  But,  notwithstanding 
these  hindrances  and  delays,  the  trip  to  and 
from  Bladensburg  was  accomplished  in  one 
minute  less  than  two  hours.  The  cells  were 
made  of  light  earthenware,  for  the  purpose  of 
experiment  merely,  without  reference  to  dura- 
bility. This  part  of  the  apparatus  could  there- 
fore easily  be  guarded  against  mishap.  The 
great  point  established  was  that  a  locomotive, 
on  the  principle  of  Professor  Page,  could  be  made 
to  travel  nineteen  miles  an  hour.  But  it  was 
found  on  subsequent  trials  that  the  least  jolt, 
such  as  that  caused  by  the  end  of  a  rail  a  little 
above  the  level,  threw  the  batteries  out  of  work- 


ing order,  and  the  result  was  a  halt.  This, 
defect  conJd  not  be  overcome,  and  Professor 
Page  reluctantly  abandoned  his  experiments  in 
this  special  direction. 

It  is  interesting  here  to  note  that  in  1847,  the 
versatile  and  unwearying  investigator,  Pro- 
fessor Moses  G.  Farmer,  constructed  and  exhib- 
ited in  public  an  electro-magnetic  locomotive, 
drawing  a  little  car  that  carried  two  passengers 
on  a  track  a  foot  and  a  half  wide.  He  used 
forty-eight  pint  cup  cells  of  Grove  nitric  acid 
battery.  In  1851,  Mr.  Thomas  Hall,  of  Boston, 
then  at  work  for  Mr.  Daniel  Davis,  constructed 
and  exhibited  at  the  Charitable  Mechanics  Fair 
in  Boston,  the  little  locomotive,  Fig.  24. 

Our  illustration  is  taken  direct  from  the  orig- 
inal woodcut  of  the  locomotive.  The  block 
was  made  nearly  thirty-seven  years  ago,  and 
first  appeared  in  Palmer  &  Hall's  catalogue  of 
1850.  The  engine  which  it  represented  was  on 


FIG.  24. — HALL  LUCOMDTIVK  OK  1850-1. 

the  principle  of  an  electro-magnet  revolving 
between  the  poles  of  a  permanent  magnet. 
The  armature  had  a  worm  on  its  shaft  which 
matched  into  a  gear  attached  to  the  driving- 
wheels,  the  latter  being  insulated  by  ivory. 
The  track  was  laid  in  five-foot  sections,  and 
was  about  forty  feet  long  and  five  inches  wide. 
Under  the  platform  of  the  car  was  a  pole- 
changer  attached  to  a  lever;  when  the  engine 
reached  the  end  of  the  track  it  ran  against  an 
inclined  plane  which  reversed  the  pole-changer 
and  sent  the  engine  to  the  other  end  of  the 
track,  where  the  same  thing  was  repeated: 
thus  the  engine  was  sent  automatically  from 
one  end  to  the  other.  The  current,  produced 
by  two  Grove  cells,  was,  it  is  well  to  note,  con- 
veyed to  the  engine  by  the  rails.  We  have 
seen,  also,  a  photograph  of  the  "Volta,"  a 
finely-constructed  model,  which  was  made  on 
the  same  principle  as  the  above,  but  so  as  to 
resemble  very  closely  a  locomotive  actuated  by 
steam.  Mr.  Hall  says  that  in  1852  he  made, 
for  Dr.  A,  L.  Henderson,  of  Buffalo,  a  model 


EARLY   MOTORS  AND   EXPERIMENTS  IN  AMERICA. 


21 


line  of  railroad  with  electric  engine,  with 
depots,  telegraph  line,  and  electric  railroad  sig- 
nals, together  with  a  figure  operating  the  sig- 
nals at  each  end  of  the  line  automatically. 
This,  he  states,  was  the  first  model  of  railroad 
signals  or  trains  worked  hy  telegraph  signals. 

Professor  Page,  in  1854,  patented  a  modifica- 
tion of  his  early  ideas.  Figs.  25  and  20.  This 
later  motor  resembled  in  external  appearance,  to 


FIG.  25. — PAGE  MOTOR. 

some  extent,  a  double-action,  slide-valve  steam 
pump.  This  Page  motor  comprised  two  par- 
allel axial  bars  working  through  two  pairs  of 
helices,  and  two  fixed  armatures  arranged  at 
either  extremity  of  the  parallel  bars.  The  pit- 
man-rod connected  the  crank  of  the  fly-wheel 
to  the  cross-head  of  the  axial  bars.  The  two 
pairs  of  helices  were  each  connected  by  wires 
with  the  two  conducting  springs  shown  in  the 
detail  view,  each  bearing  alternately  against 
the  cut-off  on  the  fly-wheel  shaft.  This  con- 
nection was  made  by  means  of  the  wires  pass- 
ing down  under  the  base-board  and  up  through 


Fio.  26. — PAGE  MOTOR. 

to  their  respective  connections,  as  shown  by 
the  dotted  lines.  This  fly-wheel  cut-off  or  com- 
mutator consisted  of  two  semi-cylindrical  me- 
tallic segments  insulated  from  each  other  and 
secured  to  a  cylinder  of  wood  upon  the  shaft. 
An  entire  metallic  ring  was  fixed  upon  a  part 
of  the  wooden  cylinder  of  less  diameter  than 
that  to  which  the  insulated  segments  were 
attached.  This  ring  was  connected  by  a  strip 


of  metal  with  one  of  the  metallic  segments. 
The  three  conducting  springs  are  shown  in  po- 
sition in  the  detail  view. 

The  spring  in  contact  with  the  smaller  ring 
connected  with  the  positive  pole  of  the  source 
of  electrical  energy,  and  the  current,  therefore, 
passed  through  the  metallic  connections  to  the 
spring  at  the  left-hand  side  of  the  detail  figure. 
This  latter  spring  was  connected  with  one  ter- 
mination of  the  helices  to  the  left  of  the  draw- 
ing, the  other  being  connected  with  the  nega- 
tive pole.  The  commutator  revolved  in  the 
direction  of  the  arrow.  The  axial  bars  are 
shown  with  thin  poles  passed  entirely  through 
the  helices  and  within  the  influence  of  the  ar- 
mature. The  instant  the  dead  point  was 
reached,  the  other  pair  of  helices  was  charged 
to  propel  the  frame  of  axial  bars  in  the  oppo- 
site direction.  This  was  effected  by  the  revo- 


FIG.  27. — STEIN  MOTOK  WITH  FAN. 

lution  of  the  commutator  in  the  direction  of  the 
arrow,  the  metallic  segments  being  reversed. 
The  very  short  distance  through  which  the  mag- 
nets acted  with  power,  and  the  rapid  diminu- 
tion of  power  as  the  magnets  receded  from  each 
other,  presented  serious  practical  difficulties  in 
this  as  in  other  electro^ magnetic  engines, 
whether  in  the  reciprocating  or  rotary  form. 
Dr.  Page  asserted  that  by  the  employment  of  a 
reciprocating  core  arranged  to  move  in  the  line 
of  its  length  through  an  arrangement  of  heli- 
ces, the  magnetic  power  could  be  made  to  act 
with  more  uniformity  through  a  considerable 
distance,  as  some  portion  of  the  magnetic  core 
would  be  always  in  close  proximity  to  the  helix. 
In  the  latter  part  of  1854,  Louis  Stein  devised 
an  electric  motor  for  operating  a  revolving 
fan,  Pig.  27.  The  device  was  intended  to  be 
attached  to  the  ceiling  in  the  manner  now 
familiar.  The  main  pendent  vertical  shaft 
carried  the  wings  of  the  fan.  This  shaft  had  a 


22 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


worm-wheel  keyed  to  it,  and  to  the  armature 
shaft  of  the  electric  motor  was  affixed  a  worm 
which  meshed  with  the  worm-wheel  and  re- 
volved the  fan.  The  electro-magnets  were 
arranged  at  equal  distances  apart  around  the 
horizontal  shaft.  Armatures  were  arranged  at 
suitable  distances  around  the  series  of  electro- 
magnets, so  that  when  the  battery  was  in  action 
the  shaft  was  kept  in  motion  and  the  fan  re- 
volved. This  patent  of  Stein  was  more  on  an 
application  of  the  electric  motor  than  an  im- 
provement in  the  motor  itself. 

The  electric  motor  of  Maurice  Vergnes,  Figs. 
28,  29  and  30,  comprised  four  wheels  or  discs 
composed  of  wood  and  revolving  upon  a  com- 
mon axle.  Each  disc  included  an  electro-mag- 
net arranged  thereon  diametrically  on  both 
sides  of  the  disc,  so  that  the  magnets  were 
parallel.  Each  pair  of  the  magnets  communi- 
cated with  a  separate  battery  and  revolved  in 
a  peculiarly  arranged  "  multiplying  coil,"  the 
coils  being  side  by  side  and  parallel  to  each 
other.  There  were  two  of  these  multiplying 


pair  was  exerting  its  greatest  force.  The  con- 
ducting power  of  the  multiplying  coil  was  said 
to  be  equal  to  the  conducting  power  of  the  elec- 
tro-magnet revolving  therein. 

By  referring  to  the  drawings  it  will  be  seen 
that  the  magnets  were  straight  bar  magnets 


FIGS.  28  AND  29. — VERGNES  MOTOR. 

coils,  which  communicated  with  separate  bat- 
teries, which,  together  with  the  separate  bat- 
teries requisite  for  the- electro-magnets,  made 
in  all  four  distinct  batteries  of  equal  intensity. 
By  means  of  pole-changers  the  direction  of  the 
electric  current  was  reversed  in  the  multiplying 
coils  at  every  half  revolution  of  the  wheels,  and 
in  each  pair  at  the  moment  when  the  other 


FIG.  30. — VERGNES  MOTOR. 

and  that  the  multiplying  coils  or  helices  formed 
an  inclosing  horizontal  band  through  which  the 
discs  and  their  magnets  revolved.  The  cur- 
rents  in  the  two  multiplying  coils  were  reversed 
alternately  so  as  to  produce  a  continuous  revo- 
lution of  the  electro  -  magnets  without  any 
change  in  their  polarity.  The  commutator 
was  arranged  on  the  shaft  between  the  two 
pairs  of  rotating,  magnet-carrying  discs. 

Maurice  Vergnes  in  1800  again  appeared  in 
the  field  of  electricity,  with  an  improvement 
upon  the  electric  motor  just  described. 

Instead  of  employing  two  distinct  sets  of  elec- 
tro-magnets revolving  in  double  stationary  hel- 
ices, he  now  used  a  single  wheel,  the  spokes  of 
which  were  electro-magnets  turning  within  a 
single  set  of  helices.  The  distinguishing  feat- 
ure of  the  later  construction  was  the  disposi- 
tion of  the  series  of  electro  -  magnets  011  a 
common  axle  and  revolving  within  stationary 
helices,  so  that  all  the  electro-magnets  had,  when 
passing  through  one  end  of  the  helices,  a  like 
polarity,  and  vice  versa.  Vergnes  asserted  that 
by  this  arrangement  he  obtained  a  continuous 
rotary  motion  without  any  dead  point,  and 
could  develop  considerable  power.  His  second 
device  is  illustrated  in  Fig.  31.  The  two  rec- 
tangularly arranged  helices,  within  which  the 
magnet -carrying  wheel  revolved,  were  sup- 
ported in  a  horizontal  position  upon  a  table  or 
frame,  as  shown  in  the  figure.  The  magnetu. 


EARLf   MOTORS  AND  EXPERIMENTS  IN  AMERICA. 


23 


wheel  revolved  wiihin  these  helices,  the  axle  of 
which  passed  between  them.  The  wheel  itself 
was  composed  of  two  flat  electro  -  magnets 
placed  at  right  angles  with  each  other,  and  on 
a,  common  centre  on  the  shaft.  The  disposition 
of  the  elements  of  this  apparatus  was  such  that 
when  one  electro-magnet  approached  an  incli- 
nation of  forty-five  degrees  with  the  helices  in 


FIG.  31. — MODIFIED  VERGNKS  MOTOR. 

its  rotation,  the  current  passed  into  the  magnet. 
The  other  bar  magnet  was  energized  in  the 
same  manner.  The  commutator  was  provided 
with  anti-frictional  contact  electrodes. 

The  patent  of  Yeiser,  granted  in  1858,  em- 
ployed what  was  at  that  date  a  novel  mechan- 
ical arrangement  for  obtaining  the  full  measure 
of  the  attractive  power  of  an  electro-magnet 
upon  its  armature.  The  operation  of  this  de 
vice  will  be  readily  apparent  from  an  inspection 
of  Fig.  32.  A  series  of  balance  beams  arranged 
one  above  the  other  was  employed.  To  both 
ends  of  these  beams  were  attached  armatures 
of  equal  weight,  which  came  into  the  magnetic 
field  successively  and  were  attracted  to  the 
magnets  so  that  each  one  in  turn  became  mo- 
mentarily in  effect  an  elongation  and  a  part  of 
the  electro-magnet.  At  each  end  of  the  ma- 
chine was  arranged  a  series  of  upright  electro- 
magnets side  by  side,  so  that  all  their  poles 
were  in  the  same  horizontal  plane.  The  cir- 
cuits of  the  two  series  of  magnets,  were,  how- 
ever, independent  of  each  other.  The  length  of 
the  series  of  armatures  was  sufficient  to  cover 
the  poles  of  all  the  magnets  at  each  end. 

The  commutator  for  closing  the  circuits  alter- 
nately through  the  two  series  of  magnets  was 
mounted  upon  the  driving  shaft  above  the 


armature  beams.  The  commutator  consisted 
of  a  wheel,  one-half  of  the  periphery  of  which 
was  insulated  in  the  usual  way.  The  circuit 
was  changed  from  one  to  the  other  of  the  series 
of  magnets  twice  in  every  revolution  of  the 
shaft. 

The  distance  between  the  horizontally  ar- 
ranged armature  beams  was  such  that  the 
beams  had  a  limited  amount  of  movement  in- 
dependent of  each  other,  the  lower  beam  being 
pivoted  so  that  it  could  have  no  more  vibratory 
movement  than  that  of  the  several  beams  piv- 
oted above  it. 

In  the  electric  motor  patented  to  Lewis  H. 
McCullough,  February  26,  1867,  a  vertically 
arranged  vibratory  armature-carrying  beam 
was  the  main  feature.  Fig.  33  is  an  illustra- 
tion of  the  McCullough  motor.  Two  pairs  of 
electro -magnets,  one  above  the  other,  were 
arranged  on  both  sides  of  the  vertical  oscillat- 
ing beam,  and  so  that  the  double  armatures  lay 
in  the  same  horizontal  plane  as  the  magnets. 


FIG.  32. — YEISER  MOTOR. 

Each  pair  of  armature  plates  was  equidistant 
from  the  pivotal  point  of  the  axis  of  the  vibrat- 
ing beam.  Attached  to  the  upper  end  of  the 
beam  by  means  of  a  wrist-pin  was  a  pitman 
through  which  rotary  motion  was  communi- 
cated. An  endwise  disposition  of  the  magnets 
for  the  purpose  of  increasing  or  diminishing 
their  attractive  force  was  accomplished  by  ad- 
justing screws  at  the  rear  of  the  magnets.  The 
lower  oscillating  end  of  the  vertical  beam  was 
arranged  to  make  and  break  the  electrical  con- 


24 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


nection  between  the  oppositely  arranged  mag- 
nets. McCullough  stated  that  in  the  operation 
of  his  motor  there  was  no  positive  breaking  of 
the  current  at  any  point  in  the  vibration  of  the 


FIG.  33. — McCuLLOuGii  MOTOR. 

central  beam,  and  that  as  a  consequence,  there 
was  no  loss  of  the  electrical  or  exciting  force 
upon  the  magnets. 

On  April  2,  1867,  Chas.  J.  B.  Gaume,  of  Iowa, 
patented  an  electro-magnetic  engine  of  which 
a  side  elevation  in  Fig.  34,  and  a  plan  view  in 
Fig.  35  are  shown.  In  the  Gaume  construction 
a  series  of  electro-magnets  were  placed  on  the 
periphery  of  a  wheel,  and  journaled  to  the 
same  axis  was  another  wheel  revolving  be- 
tween the  adjacent  magnets,  carrying  a  series 
of  armature  plates  attracted  successively.  The 
battery  wires  were  so  connected  through  the 
motor  that  a  reserve  power  might  be  attached 
or  detached  by  the  motion  of  a  governor  upon 
the  engine,  the  speed  of  which  determined  the 
battery  connection. 

By  an  inspection  of  the  figures  it  will  be  seen 
that  the  electro-magnets  were  mounted  upon 
the  horizorvtll  'haft,  the  wheel  carrying  the 
armatures  being  mounted  upon  the  same  shaft. 


but  revolving  in  an  opposite  direction.  Each 
of  these  wheels  carried  a  bevel  pinion,  .and 
both  meshed  with  a  third  bevel  gear,  mounted 
upon  a  vertical  shaft,  to  which  the  governor 
was  attached.  The  wires  of  the  electro-mag- 
nets were  led  to  the  commutator  in  the  usual 
manner. 

Below  the  armature  beams  and  between  the 
magnets  was  a  supplementary  oscillating  arm, 
having  pivoted  to  its  outer  ends  two  upright 
rods,  the  upper  ends  of  which  were  attached  to 
the  beam  which  carried  the  topmost  pair  of  ar- 
matures. To  the  ends  of  the  lower  oscillating 
beam  were  also  pivoted  two  crank  arms  or  pit- 
men, the  upper  ends  of  which  were  coupled  to 
the  driving  shaft  by  means  of  crank  arms.  As 
all  of  the  series  of  bars  which  were  operated 
upon  came  down  as  close  as  possible  together 
within  the  magnetic  field  of  each  pole,  the  com- 
mutator broke  the  circuit  of  that  series  of  mag- 
nets and  closed  the  circuit  of  the  other  series, 
whereby  the  other  ends  of  the  series  of  bars 
were  brought  into  action.  In  this  way  an 


FIG.  34. — GAI-MK  MOTOR. 

oscillating  motion  of  the  beams  was  produced, 
and  the  upper  beam  served  through  its  connec- 
tions to  produce  a  rotary  motion  of  the  driving 
shaft.  When  the  circuit  was  first  closed 
through  the  series  of  magnets  the  lowest  of  the 
corresponding  series  of  armature  bars  was 
attracted  directly  to  the  magnets,  and  by  its 


EARLY  MOTORS  AND   EXPERIMENTS  IN  AMERICA. 


25 


movement  all  the  other  armatures  opposite, 
whose  ends  rested  upon  each  other,  were  caused 
to  move  a  corresponding  distance,  upon  which 
the  lowest  bar  became  magnetic,  attracted  the 
second  one  and  drew  it  down  in  contact  with 
it,  thus  giving  all  the  beams  a  further  move- 


Fra.  35. — .GAUME  MOTOR. 

merit.  The  second  bar,  as  it  came  in  contact 
with  the  first,  became  magnetic  and  attracted 
the  third,  and  so  on  through  the  series  till  all  the 
bars  were  in  contact,  as  shown  in  the  figure. 

The  electric  governor  was  of  the  usual  pivoted 
ball  construction,  and  revolved  upon  a  sliding 
collar  on  a  vertical  shaft  rotated  by  an  arrange- 
ment of  bevel  wheels,  as  before  indicated. 
When  the  balls  rose  under  increase  of  speed, 
a  central  rod  was  depressed,  raising  by  an 
arrangement  of  levers  the  horizontal  pivoted 
circuit  breaker  shown  at  the  bottom  of  the  side- 
elevation. 

This  circuit  breaker  or  switch  had  three  keys, 
which,  when  the  switch  was  in  a  horizontal 
position  were  in  contact  with  three  correspond- 
ing plates  to  which  were  attached  wires  from 
auxiliary  batteries.  When  the  governor  reached 
a  certain  high  speed  it  disconnected  one  of  the 
keys  and  consequently  one  of  the  sources  of 
electrical  power.  If  the  speed  still  increased, 
the  electrical  connection  between  the  second  or 

4 


central  key  was  broken,  and  so  on.  Thus  it 
will  be  seen,  the  amount  of  electrical  power 
was  graduated  to  the  speed,  the  successive  con- 
nections being  severed  as  the  speed  increased, 
and,  conversely,  being  restored  when  the  speed 
decreased. 

As  is  usual  with  this  type  of  machine,  a  de- 
terminate impulse  in  a  given  direction  having 
been  communicated  to  the  wheels,  their  impetus 
carried  them  in  the  intervals  of  time  when  the 
electric  circuit  was  broken,  and  the  electric  im- 
pulse being  imparted  at  a  certain  period,  the 
armatures  were  individually  attracted  toward 
the  electro-magnet  next  in  series,  and  an  addi- 
tional impulse  was  obtained,  producing  an  in- 
crement of  speed. 

The  principal  feature  of  novelty  in  the  elec- 
tric motor  which  William  Wickersham  patented 
June  2, 1808,  arid  is  shown  in  Fig.  30,  was  the  em- 
ployment of  an  endless  electro-magnetic  chain, 
the  alternate  links  of  which  were  magnetic 
bars,  the  remaining  connecting  links  being 
non-magnetic.  The  magnetic  links  were  sur- 
rounded by  helices  through  which  an  electric 
current  passed. 


FIG.  3(5. — WICKERSHAM  MOTOH. 

The  machine  itself  had  two  of  these  endless 
magnetic  chains,  arranged  vertically  on  par- 
allel shafts  so  as  to  revolve  thereon.  The  bars 
of  the  chain,  at  fixed  periods  in  their  revolution, 
passed  through  helices  having  hollow  cores. 

The  strips  of  metal  of  which  the  stationary 
helices  were  formed,  extended  at  one  end 
of  the  motor  beyond  the  helices,  and  were 
arranged  in  parallel  lines.  A  commutator. 


26 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


consisting  of  a  vertically  arranged  revolving 
cylinder,  had  metal  conductors  in  the  shape  of 
strips  of  metal  placed  at  intervals  around  it. 
These  conductors  were  wound  spirally,  and  ex- 
tended from  one  end  of  the  cylinder  to  the 
other.  The  extended  ends  of  the  helices  before 
referred  to  were  arranged  so  as  to  wipe  this 
revolving  commutator,  and  thus  close  the  cir- 
cuit successively  in  the  different  helices.  The 
closing  of  the  circuit  in  the  independent  series 
of  coils  which  constituted  the  completed  helices, 
was  made  successively  from  one  end  to  the  other 
of  each  helix,  and  at  the  same  speed  that  the  mag- 
netic endless  chain  moved  in  passing  through  the 
helices.  This  was  effected  by  the  spiral  form  of 
the  conductors  in  the  commutator. 

The  motor  was  adapted  to  be  stopped  or  re- 
versed, the  commutator  being  vertically  ad- 
justable upon  its  shaft  for  this  purpose.  This 
commutator,  which  Wickersham  styled  a  "  cir- 
cuit-cylinder," had  a  rod  arranged  in  a  parallel 
position  with  it  and  passing  through  the  base, 
by  means  of  which  the  vertical  adjustment  of 
the  commutator  was  accomplished.  On  the 
upper  end  of  this  rod  was  secured  a  freely  re- 
volving washer,  which  rotated  within  a  groove 
near  the  lower  end  of  the  commutator.  The 
rod  itself  had  three  grooves  within  it,  in  any 
one  of  which  the  spring  stop  bolted  to  the  side 
of  the  machine  could  rest.  When  this  rod  was 
raised  or  depressed,  the  commutator  moved 
with  it  and  thus  was  held  at  any  vertical  ele- 
vation determined  by  the  three  grooves  in  the 
rod.  When  the  commutator  was  moved  to  its 
highest  position  the  engine  ran  forward;  at  its 
lowest  position  the  commutator  reversed  the 
motor,  while  at  its  intermediate  position  the 
adjustable  commutator  brought  the  motor  to  a 
state  of  rest. 

The  independent  coils  which  constituted  the 
helices  were  wound  in  different  directions,  and 
each  one  conducted  the  electric  current  around 
the  magnetic  link  of  the  endless  chain  in  a  dif- 
ferent direction  from  the  one  preceding  it, 
thereby  giving  to  the  magnetic  links  alternate 
reversed  polarities.  When  two  columns  of  hel- 
ices were  used  on  opposite  sides  of  the  machine 
(the  magnet  chain  passing  downward  through 
the  one  and  upward  through  the  other),  the  at- 
traction of  the  former  would  be  downward  and 
that  of  the  latter  upward. 

The  motor  constructed  by  Charles  T.  Mason 
and  that  made  by  Mr.  A.  J.  B.  DeMorat  com- 


plete the  list  of  patented  motors,  the  terms  of 
protection  of  which  expired  up  to  the  end  of 
1885,  so  that  our  review  of  some  of  the  early 
American  motors  may  well  end  at  this  point. 

Mason's  motor,  Fig.  37,  was  designed  for  driv- 
ing a  fan.  It  consisted  of  an  electro-magnet, 
one  terminal  of  the  coil  of  which  was  connected 
to  the  binding  post  shown  in  the  illustration, 
and  the  other  to  the  spindle  of  the  fan  shaft. 
The  armature  of  the  electro-magnet  is  shown 
pivotally  secured  to  the  fan  shaft  above  the 
the  electro-magnet.  The  fan  spindle  also  car- 
ried a  cam  which,  as  it  revolved,  broke  and 


FIG.  37. — MASON  MOTOR. 

made  connection  with  the  horizontal  wiping 
spring  secured  to  a  standard  at  the  left  of  the 
figure.  The  cam  and  wiping  spring  formed  the 
commutator  of  the  motor. 

De  Morat's  motor  is  shown  in  side  elevation 
and  in  vertical  section  in  Fig.  38.  De  Morat 
asserted  that  there  was  no  interruption  or 
breaking  of  the  current  in  the  use  of  this  motor, 
such  a  result  never  having  been  practically  ac- 
complished before,  and  that  greater  velocity, 
more  regular  and  constant  motion,  with  greater 
power,  could  be  obtained  from  his  construction 
than  from  any  other  similar  machine  patented 
before  that  date. 

By  referring  to  the  drawing  it  will  be  seen 
that  the  lower  wheel  represents  a  circular  mag- 
net of  two  or  more  poles.  The  central  disc  of 
this  wheel  was  of  iron,  with  contiguous  coils  of 
wire  on  either  side,  the  whole  being  clamped 
together  with  wooden  discs.  The  commutator 


EARLY  MOTORS  AND  EXPERIMENTS  IN  AMERICA. 


27 


was  also  fixed  upon  the  shaft  of  this  circular  mag- 
net. It  consisted  of  two  metal  bands  insulated 
from  each  other  and  electrically  connected  with 
two  wiping  springs  which  completed  the  circuit. 
Above  this  circular  magnet  was  a  wheel  of 
many  armatures.  This  wheel  consisted  of  a 
number  of  radial  arms  which  had  flanges  to 
receive  the  separate  armatures  composing  the 
wheel.  Each  of  these  armatures  had  an  inde- 
pendent radial  movement  within  the  flanges  of 
the  wheel,  but  without  touching  the  circum- 
ference of  the  same.  Each,  in  addition,  had 


Fici.  38.— DE  MORAT  MOTOR. 

an  inward  extension  stem  or  shank,  which  was 
held  in  operative  position  by  lugs  upon  the 
wheel  frame.  Coiled  springs  surrounded  these 
stems  between  the  lugs,  and  had  a  constant 
tendency  to  force  the  armatures  outward  when 
not  held  inward  by  the  latches.  A  projecting 
arm  was  bolted  to  the  inner  side  of  one  of  the 
standards,  on  the  end  of  which  the  outer  ends 
of  the  latches  of  the  armatures  struck.  This 
movement  lifted  the  latches  out  of  the  notches 
in  the  armatures,  and  the  springs  forced  them 
outward,  as  shown. 

As  soon  as  the  circular  magnet  was  ener- 
gized, the  armatures  were  attracted  angularly, 
producing  a  motion  by  the  tendency  to  make 
contact.  This  was  not  possible  without  pro- 
ducing two  motions,  one  causing  the  system  to 
revolve,  the  other  sending  the  armatures  in- 


ward by  their  contact  with  the  magnet,  and 
fastening  them  there  by  the  latches  dropping 
into  the  notches  on  the  armatures.  In  that 
position  they  passed  beyond  the  magnetic  field 
until  released  by  the  projection  on  the  frame. 

De  Morat  contemplated  reversing  the  relative 
arrangement  of  the  motor  by  converting  the 
armatures  into  electro  -  magnets  and  causing 
them  to  exert  an  attraction  011  different  curves 
or  on  a  number  of  planes  tangent  to  the  circle 
in  the  form  of  a  polygon,  as  shown  in  the  small 
sketch  representing  a  hexagon.  The  attraction 
would  then  be  effected  so  as  to  form  an  endless 
chain  or  elastic  band. 

It  deserves  notice  that  between  1860  and 
1867 — the  period  of  the  civil  war — not  a  single 
patent  was  issued  in  America  011  electric  motors. 
A  war  to-day  would  probably  be  highly  stimu- 
lative of  inventiveness  in  this  direction.  But 
down  to  1860,  the  interest  that  had  begun  to 
manifest  itself  twenty  years  earlier,  contin- 
ued in  almost  undiminished  measure.  A  lively 
sketch  of  the  condition  of  affairs  during  that 
period  was  given  by  Dr.  Vander  Weyde  in  May, 
1886,  before  the  New  York  Electrical  Society. 
Dr.  Vander  Weyde  was  commissioned  by  the 
late  Mr.  Peter  Cooper  to  examine  the  various 
motors  that  were  submitted  by  inventors  who 
desired  to  obtain  capital  for  the  furtherance  of 
their  work;  and  it  was  well  for  the  distin- 
guished philanthropist  that  he  could  enjoy  the 
services  of  one  so  competent,  and  of  one.  too, 
who  by  continuous  experiments  between  1843 
and  1848  had  already  satisfied  himself  that  the 
electric  motor  could  never  be  substituted  to  any 
extent  for  other  motors  so  long  as  the  main 
dependence  was  upon  chemical  batteries. 

"Invariably  I  felt  obliged  to  advise  ad- 
versely," says  Dr.  Vander  Weyde,  "and,  while 
Mr.  Cooper  was  very  slow  to  invest  in  un- 
certain enterprises,  in  some  instances  a  great 
pressure  was  brought  to  bear  upon  him  by 
enthusiastic  inventors  and  their  still  more  en- 
thusiastic friends,  to  whom  he  might  have 
yielded  if  my  convictions,  in  which  he  ap- 
peared to  have  much  confidence,  had  not 
prevented  it.  Those  examinations  took  place 
off  and  on  during  the  whole  period  of  the 
erection  of  the  Cooper  Union  building,  which 
was  completed  in  1859,  when  I  was  appointed 
one  of  the  teachers.  I  believe  Mr.  Cooper  never 
spent  a  single  dollar  on  account  of  electro- 
motors, except  on  such  small  specimens  as  were 


28 


THE   ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


required  for  class  instruction  in  the  regular 
course  of  lectures  in  physical  science  given  in 
the  Cooper  Union  building. 

"The  electro-motors  I  examined  differed 
greatly  in  size,  from  such  as  occupied  scarcely 
the  space  of  a  cubic  foot  to  those  of  the  size  of 
a  50  horse-power  steam  engine.  Among  the 
latter  I  must  mention  the  motors  of  three  in- 
ventors who  operated  on  a  large  scale,  viz., 
Professor  Page,  of  Washington;  Professor 
Vergnes,  of  New  York,  and  Mr.  Paine,  of 
Newark.  I  saw  Page's  engine  in  operation  in 
New  York  in  1850.  His  system  is  well  known 
among  electricians,  but  deserves  special  men- 
tion for  the  large  scale  on  which  he  executed  it. 
It  consisted  in  massive  iron  plungers  which 
were  attracted  into  coils  by  alternate  currents, 
and  by  means  of  a  crank  they  revolved  a  fly- 
wheel. Vergnes'  machine  was  exhibited  at  our 
World's  Fair  in  1852,  in  the  Crystal  Palace  on 
Reservoir  Square — now  called  Bryant  Park— 
and  consisted  in  elongated  loops  of  copper  wire 
revolving  between  the  poles  of  powerful  and 
colossal  electro-magnets.  In  regard  to  this  ma- 
chine, I  will  remark  that  if  he  had  reversed  the 
function  of  his  machine  and  revolved  the  loops 
by  means  of  steam  power,  he  would  have  had 
one  of  the  forms  of  Siemens'  dynamos,  and 
would  have  solved  the  problem  reserved  for  the 
investigators  of  twenty  years  later  (Pacinotti, 
Gramme  and  Siemens),  who  transformed  power 
into  electric  currents  by  the  inverson  of  the 
function  of  the  motor,  as  Gramme  did  with 
Pacinotti's  ring.  In  fact,  one  of  the  little 
motors  which  I  constructed  in  1844  would  have 
been  a  small  dynamo,  if  revolved  with  suffi- 
cient power  and  velocity. 

"For  driving  their  large  motors,  both  Page 
and  Vergnes  used  proportionally  large  bat- 
teries— large  in  size  as  well  as  in  the  number  of 
cups.  Their  batteries  were  always  carefully 
hidden  from  view,  especially  those  used  by 
Vergnes,  who  had  in  the  Crystal  Palace  several 
locked  rooms  which  were  filled  with  them. 

"  Paine,  of  Newark,  did  not  need  any  battery 
at  all  for  exhibition  of  his  motor.  He  had, 
however,  a  small  battery  connected  with  his 
motot,  and  pretended  that  this  did  drive  it,  to- 
gether with  the  circular  saw  connected  with  the 
same.  This  saw  operated  with  such  power  that 
it  aroused  my  suspicions,  so  I  surreptitiously 
disconnected  the  battery,  and  as  the  saw 
worked  just  as  well  I  was  convinced  that  power 


was  obtained  from  elsewhere.  I  then  dis- 
covered that  next  door  there  was  a  factory 
where  steam-power  was  used,  and  that  Paine's 
electro-motor  was  only  on  exhibition  during  the 
working  hours  of  the  factory.  The  whole  de- 
ception was  clear,  the  only  purpose  being  to  sell 
stock  in  Mr.  Paine's  electro-motor  company, 
which  was  kept  up  for  several  years,  but  has 
been  put  in  the  shade  by  the  strong  vitality  of 
the  Keely  motor  enterprise  of  the  present  day." 
This  chapter  should  not  close  without  mention 
of  Pinkus,  who  early  conceived  an  ingenious 
method  of  operating  an  electric  railway.  Dr. 
Wellington  Adams,  of  St.  Louis,  in  a  paper 
read  in  1884,  before  the  engineers'  club  of  that 
city,  gave  some  interesting  details  of  the  man- 
ner in  which,  when  working  upon  the  idea  of 
a  railway  whose  motors  picked  up  their  current 
from  the  rails,  he  was  referred  to  the  work  of 
his  predecessor.  "  Although  at  the  time  (1870) 
actively  engaged  in  medical  practice,  and  con- 
nected with  the  Medical  College  in  Denver,  so 
great  were  the  allurements,  that  I  was  induced 
to  give  up  everything  in  Colorado  and  leave 
there  rather  precipitately  for  Washington,  in 
quest  of  a  generic  claim  upon  this  funda- 
mental principle.  My  case  being  examined,  it 
was,  however,  found  that  the  same  principle 
had  been  proposed  and  provisionally  patented, 
as  far  back  as  1840,  by  one  Henry  Pinkus,  a  re- 
markably inventive  genius  of  that  period.  In 
1840,  however,  the  dynamo  was  unknown,  and 
the  electric  car  motors  of  Pinkus,  which  ex- 
isted only  in  his  imagination,  were  supposed  to 
be  operated  by  galvanic  batteries  buried  in  the 
ground.  The  principle  of  the  transmission  of 
the  current  to  the  car  while  in  motion  for  the 
purpose  of  effecting  its  propulsion  was,  how- 
ever, the  same.  The  inventor  even  went  so  far 
as  to  anticipate  the  future  use  of  '  mechanical 
generators  which  should  be  more  economical 
than  the  batteries.'"  Pinkus  was  but  another  of 
those  who  were  allowejl  to  see  the  promised 
land,  but  were  unable  to  enter.  Mention  may 
also  be  made  here  of  the  electric  locomotive  de- 
vised in  1847  by  Mr.  Lilley  and  Dr.  Colton,  of 
Pittsburgh.  This  locomotive  was  driven  around 
a  circular  track  by  electricity.  The  rails  were 
insulated,  each  connecting  with  a  pole  of  the 
battery,  and  the  current  was  taken  up  by  the 
wheels,  whence  it  passed  to  the  magnets,  upon 
whose  alternate  attraction  and  repulsion  mo- 
tion depended. 


CHAPTBR    IV. 


THE  ELECTRICAL  TRANSMISSION  OK  POWER. 


WHEN  Dr.  Antonio  Pacinotti  described  his 
"  Electro-Magnetic  Machine "  in  the  Italian 
periodical  //  Nuovo  Cimento,  in  June,  1864,  he 
mentioned  the  fact  that  the  machine  could  be 
used  either  to  generate  electricity  on  the  appli- 
cation of  motive  power  to  the  armature,  or  to 
produce  motive  power  on  connecting  it  with  a 
suitable  source  of  current.  This,  so  far  as  can 
be  determined,  was  the  first  mention  of  the 
now  so  well  known  principle  of  the  reversibility 
of  the  dynamo-electric  machine,  the  practical 
utilization  of  which  implies  the  development  of 
a  new  electrical  industry — the  electrical  trans- 
mission of  mechanical  energy. 

Probably  Dr.  Pacinotti  himself  did  not  real- 
ize that  even  while  he  was,  for  the  first  time, 
disclosing  the  principle  of  construction  that 
was  destined  to  make  the  dynamo-electric  ma- 
chine practical  and  efficient,  he  was  demon- 
strating this  principle  of  reversibility  which 
promises  to  multiply  the  application  and  utility 
of  dynamo-electric  machines  tenfold.  We  men- 
tion Dr.  Pacinotti's  name  here  purposely  to 
give  him  the  homage  due  for  his  valuable  re- 
searches in  this  field,  especially  inasmuch  as  it 
was  his  misfortune  to  be  too  far  ahead  of  his 
time.  His  researches  failed  to  attract  the 
attention  and  encouragement  which  they  de- 
served, and  we  might  say  that  the  same  ground 
had  to  be  travelled  over  again  by  those  who 
came  later. 

The  principle  of  the  reversibility  of  dynamo- 
electric  machines  appears  to  have  been  per- 
ceived by  Messrs.  Siemens  about  1807,  but  it 
was  not  heard  of  in  practical  application  until 
the  year  1873,  when  it  was  practically  demon- 
strated by  MM.  Hippolyte  Fontaine  and  Breguet 
at  the  Vienna  Universal  Exposition.  In  this 
case  a  Gramme  machine  used  as  a  motor  to 
work  a  pump  was  run  by  the  current  produced 
by  a  similar  machine  connected  by  more  than 
a  mile  of  cable,  and  put  in  motion  by  a  gas 
engine.  This  was  the  first  instance  of  elec- 


trical transmission  of  mechanical  energy  to  a 
distance. 

It  is  always  interesting  to  go  back  to  the  first 
dawn  of  a  new  invention,  but  it  is  not  always 
easy  to  determine  whether  it  was  the  result  of 
accident  and  necessity,  or  the  outcome  of  clear, 
intelligent  foresight  in  the  part  of  an  inventor 
working  for  a  particular  purpose.  As  regards 
the  first  transmission  of  power  by  electricity, 
opinions  are  divided.  According  to  M.  Figuier, 
accident,pure  and  simple,was  the  cause  of  the 
discovery.  He  relates  that  at  the  International 
Exhibition  of  Vienna  in  1873,  the  Gramme 
Company  exhibited  two  machines  intended  for 
plating  purposes.  One  of  these  machines  was 
in  motion,  and  a  workman  who  noticed  that 
some  cables  were  trailing  on  the  ground,  think- 
ing they  belonged  to  the  second  machine,  placed 
them  in  its  terminals.  To  the  surprise  of  every- 
body this  second  machine,  which  had  been 
standing  still,  began  to  turn  of  its  own  accord. 
Then  it  was  discovered  that  the  first  machine 
was  working  the  second. 

This  story  is  romantic,  but  disappointing  to  a 
true  lover  of  science,  who  would  prefer  to  be- 
lieve that  a  great  discovery  was  the  logical  out-- 
come  of  the  working  of  a  powerful  intellect, 
and  not  the  result  of  accidental  meddling  on 
the  part  of  an  ignorant  workman.  But  there  is 
another  version  of  the  story,  told  by  M.  Hip- 
polyte Fontaine  to  the  Societe  des  Anciens 
Eleves  des  Ecoles  Rationales  des  Arts  et  Metiers. 
M.  Fontaine  claims  to  have  actually  invented 
or  discovered  the  electrical  transmission  of 
power,  as  will  be  seen  from  the  following  short 
abstract  of  his  paper  read  before  the  above 
mentioned  society: 

"On  the  1st  of  May,  1873— that  is,  on  the 
date  fixed  four  years  previously  by  imperial 
decree — the  Exhibition  in  Vienna  was  formally 
opened.  At  that  time  the  machinery  hall  was 
yet  incomplete,  and  remained  closed  to  the  pub- 
lic until  the  3d  of  June,  when  it  was  also 


30 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


thrown  open.  I  was  then  engaged  with  the 
arrangement  of  a  series  of  exhibits,  shown  for 
the  first  time  in  public,  which  w  ^re  intended  to 
work  together,  or  separately,  as  desired.  There 
was  a  dynamo  machine  by  Gramme  for  electro- 
plating, giving  a  current  of  400  amperes  at  25 
volts,  and  a  magneto  machine,  which  I  intended 
to  work  as  a  motor  from  a  primary  battery,  or 
from  a  Plante  accumulator,  to  demonstrate  the 
reversibility  of  the  Gramme  dynamo.  There 
were  also  a  steam  engine  of  my  invention 
heated  by  coke,  a  domestic  motor  of  the  same 
type  heated  by  gas,  a  centrifugal  pump  placed 
on  a  large  reservoir,  and  arranged  to  feed  an 
artificial  cascade,  and  numerous  other  exhibits. 
To  vary  the  experiments  I  proposed  to  show,  I 
had  arranged  the  pump  in  sucli  a  way  that  it 
could  be  worked  either  by  the  Gramme  mag- 
neto machine  or  by  the  steam  engines  (Fon- 
taine). 

"  On  the  1st  of  June  it  was  announced  that 
the  machinery  hall  would  be  formally  opened 
by  the  Emperor  at  10  A.  M.  on  the  day  after  the 
morrow..  Nothing  was  then  in  readiness,  but 
those  who  have  been  in  similar  situations  know 
how  much  can  be  got  into  order  in  the  space  of 
•18  hours  just  before  the  opening  of  a  great  ex- 
hibition. In  every  department  members  of  the 
staff  with  an  army  of  workmen  under  their 
orders  were  busy  clearing  away  packing  cases 
and  decorating  the  spaces  allotted  to  the  dif- 
ferent nations.  These  gentlemen  visited  all  the 
exhibits  in  order  to  determine  which  of  them 
should  be  selected  for  the  special  notice  of  the 
Emperor,  so  as  to  detain  him  as  long  as  possible 
among  the  exhibitors  of  their  respective  coun- 
tries. 

"M.  Roullex-Duggage,  who  superintended  the 
work  in  the  Frenoh  section,  asked  me  to  set 
in  motion  all  the  machinery  on  my  stand,  and 
especially  the  two  Gramme  machines.  I  set 
about  at  once,  and  on  the  3d  of  June  I  had  the 
satisfaction  of  getting  the  large  Gramme 
dynamo,  the  two  engines  (Fontaine),  and  the 
centrifugal  pump  to  work;  but  I  failed  to  get 
the  motor  into  action  from  the  primary  or  sec- 
ondary battery.  This  was  a  great  disappoint- 
ment, especially  as  it  prevented  my  showing 
the  reversibility  of  the  Gramme  machine.  I 
was  puzzled  the  whole  of  the  evening  and  the 
whole  of  the  night  to  find  a  means  to'  accom- 
plish my  object,  and  it  was  only  in  the  morning 
of  the  3d  of  June,  a  few  hours  before  the  visit 


of  the  Emperor,- that  the  idea  struck  me  to 
work  the  small  machine  by  means  of  a  derived 
circuit  from  the  large  machine.  Since  I  had 
no  leads  for  that  purpose,  I  applied  to  the  repre- 
sentative of  Messrs.  Manhis,  of  Lyons,  who 
was  kind  enough  to  lend  me  250  metres  of  cable, 
and  when  I  saw  that  the  magneto  machine  was 
not  only  set  in  motion,  but  developed  so  much 
power  as  to  throw  the  water  from  the  pump  be- 
yond the  reservoir,  I  added  more  cable  until  the 
flow  of  water  became  normal.  The  total  length 
of  cable  in  circuit  was  then  over  two  kilo- 
metres. This  great  length  gave  me  the  idea 
that  by  the  employment  of  two  Gramme  ma- 
chines it  would  be  possible  to  transmit  mechan- 
ical energy  to  great  distances.  I  spoke  of  this 
idea  to  various  people,  and  I  published  it  in  the 
Revue  Industrielle  in  1873,  and  subsequently  in 
my  book  on  the  Vienna  Exhibition.  The  pub- 
licity thus  given  to  it  was  so  great  that  I  had 
neither  time  nor  desire  to  protect  my  invention 
by  a  patent.  I  must  also  mention  that  M. 
Gramme  has  told  me  that  he  had  already 
worked  one  dynamo  by  the  other,  and  I  have 
always  held  that  the  honor  of  my  experiment 
belongs  to  the  Gramme  Company." 

Electric  lighting  had  not  yet  left  the  labora- 
tory or  the  lecture  room,  and  the  Gramme  ma- 
chines, then  about  the  only  ones  made,  were 
all  constructed  for  electrotyping  or  electro- 
plating, and  were  consequently  ill  adapted  to 
the  purposes  of  electrical  transmission.  How- 
ever, the  demonstration  served  the  purpose  of 
M.  Fontaine,  its  author,  for  it  called  attention 
to  this  field  of  study.  In  1877  some  officers  of 
the  French  army  made  use  of  two  Gramme  ma- 
chines to  transmit  power  from  a  steam  engine 
to  a  dividing  machine,  placed  at  a  distance  of 
about  sixty  metres.  Meanwhile,  other  experi- 
menters were  at  work  in  the  same  direction  and 
it  became  a  lecture  experiment  to  work  ma- 
chinery by  an  electric  motor  operated  by  a  cur- 
rent generated  at  a  distance.  It  was  only  in 
1879,  however,  that  the  real  importance  of  the 
subject  was  made  apparent  by  MM.  Felix  and 
Chretien  in  their  experiment  at;  Sermaize  in 
plowing  by  electricity,  which  was  conducted  on 
a  practical  scale  and  caused  great  excitement. 
At  the  same  time,  1870,  the  electrical  railway 
of  Siemens  and  Halske.  which  made  its  first 
appearance  at  the  Berlin  Exhibition,  was  an  in- 
teresting and  perhaps  still  more  striking  in- 
stance of  the  possibilities  of  the  electrical 


THE  ELECTRICAL  TRANSMISSION   OF  POWER. 


31 


transmission  of  power.  The  electrical  exhibi- 
tion of  1881  at  Paris  also  afforded  to  electrical 
engineers  an  excellent  opportunity  to  demon- 
strate the  applicability  of  electrical  transmis- 
sion in  providing  motive  power  for  multifarious 
purposes.  The  currents  from  dynamo-electric 
machines  were  used  for  driving  motors  for 
sewing  machines,  lathes,  planers,  drills,  ham- 
mers and  other  workshop  machinery,  rock- 
drills,  saws,  pumps,  elevators;  and  also  for 
electric  railways,  one  of  which,  from  the  firm 
of  Siemens  &  Halske,  served  to  convey  passen- 
gers from  the  Place  de  la  Concorde  to  the 
Palais  de  1'Industrie. 

At  the  Munich  Exposition  in  1882  the  subject 
of  the  electrical  transmission  of  mechanical 
energy  did  not  fail  to  receive  a  share  of  atten- 
tion. There  were  several  practical  examples 
showing  the  production  of  motive  power  from 
electricity. 

Our  illustration,  Fig.  39,  represents  one  of 
these  installations,  a  small  workshop,  which 
derived  its  motive  power  from  a  Schuckert  ma- 
chine fed  from  a  similar  machine  placed  in 
another  part  of  the  Crystal  Palace  and  run  as 
a  generator.  M.*  Schuckert  had  also  another 
installation  for  demonstrating  the  transmission 
of  mechanical  energy  by  electricity.  In  this 
case  the  generator  was  placed  at  Hirschau  in  a 
machine  shop  supplied  with  water  power  from 
the  Isar  River.  The  motor  was  in  the  Crystal 
Palace,  and  the  distance  between  the  two  was 
about  ten  kilometres.  The  conductors  were  two 
wires  of  copper,  four  millimetres  in  diameter 
(==  No.  C  B.  and  S.)  and  had  a  total  resistance 
of  9.0  ohms.  The  power  expended  on  the  gen- 
erator was  of  about  nine  horse,  and  the  work 
done  by  the  motor,  which  was  belted  to  a  coun- 
ter-shaft furnishing  power  to  two  threshing 
machines  running  empty,  was  equal  to  about 
three  horse  power.  The  efficiency  was  there- 
fore about  one-third. 

In  another  installation,  the  Edison  "Z"  ma- 
chine was  used  as  a  motor  to  supply  motive 
power  to  a  German  "Melkerei,"  or  dairy,  such 
as  is  frequently  to  be  seen  in  the  mountains  in 
Bavaria,  where  the  power  of  water -falls  is 
made  to  move  the  churns,  skimmers  and  other 
contrivances. 

But  there  was  another  example  —  we  might 
say  proof — of  the  possibilities  of  electrical  trans- 
mission of  energy  to  a  distance,  which  made  the 
Munich  Exposition  itself  memorable,  and  com- 


pared with  which  all  other  previous  ones  paled 
into  insignificance.  We  refer  to  the  celebrated 
feat  of  electrical  transmission  of  M.  Marcel 
Deprez.  The  science  of  electrical  transmission 
of  energy  over  long  distances  may  be  said  to 
date  from  that  time,  for  it  was  in  these  experi- 
ments that  M.  Deprez  revealed  to  the  electrical 
world  the  theory  of  electrical  transmission  de- 
duced by  himself,  while  he  furnished  a  proof  by 
ocular  demonstration.  It  is  for  this  reason  that 
the  name  of  Marcel  Deprez  occupies  such  an 
important  space  in  all  discussions  bearing  on 
this  subject. 

We  may  omit  the  consideration  of  M.  Deprez's 
particular  theories  for  the  present,  however,  in 
order  to  point  out  generally  what  are  the  prin- 
ciples entering  the  problem  of  the  distribution 
of  power  by  electricity,  the  most  of  which  were 
first  demonstrated  by  Siemens  and  Deprez. 

To  convey  energy  by  means  of  electricity 
from  one  place  to  another,  three  things  are 
necessary:  a  generator,  a  motor,  and  two  con- 
ductors connecting  both.  The  generator  con- 
verts energy  out  of  its  mechanical  form  (or 
chemical,  caloric)  into  electric  energy;  the  mo- 
tor reconverts  it  into  its  mechanical  (chemical, 
caloric)  form.  But  not  all  the  electric  energy 
produced  by  the  generator  will  be  reconverted 
by  the  motor,  as  it  is  a  well  known  fact  that  if 
a  current  pass  through  a  circuit  a  certain 
amount  of  its  energy  will  appear  as  heat,  as  no 
circuit  can  be  made  without  resistance.  If  then 
W  stands  for  the  work  expended  upon  the  gen- 
erator, w  for  that  done  by  the  motor,  and  if  H  J 
be  the  mechanical  value  of  the  heat  generated 
(J  stands  for  Joule's  equivalent  and  H  for  the 
number  of  heat  units),  then,  according  to  the 
law  of  conservation  of  energy  first  enunciated 
by  Helmholtz: 


W=HJ+w. 


(I.) 


Now,  if  the  electromotive  force  of  the  gen- 
erator be  E,  and  the  resistance  of  the  circuit, 
including  generator,  motor,  and  conductors  be 
R,  then  a  current  C  would  have  to  pass  through 
the  circuit,  and,  according  to  Ohm's  law, 

E 

(7  =  —. 
R 

And  this  is  also  the  case  as  long  as  the  motor 
stands  still;  but  as  soon  as  its  armature  rotates, 
i.  e.,  the  motor  does  work,  the  current  C  sinks 


32 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


THE   ELECTRICAL  TRANSMISSION   OF  POWER. 


33 


to  Ci.  Now,  as  no  new  resistance  has  been 
added  to  the  circuit,  the  cause  of  this  falling  of 
current  can  only  be  an  electromotive  force, 
induced  by  the  magnets  of  the  motor  in  the 
rotating  coils  of  the  armature,  and  opposing  the 
electromotive  force  of  the  generator.  C\  can 
therefore  be  expressed  by  the  formula: 


E—e 
R 


(II.) 


in  which  e  stands  for  the  counter  electromotive 
force. 

In  the  preceding  and  subsequent  formulas  Mr. 
H.  M.  Schlesinger,  in  following  Professor  S.  P. 
Thompson,  has  assumed  the  generator  and  mo- 
tor to  be  such  as  to  convert  mechanical  energy 
into  electric,  and  vice  versa,  without  loss;  the 
sources  and  effect  of  such  loss  will  be  consid- 
ered later  on. 

Formula  (II.)  may  also  be  written  in  the  fol- 
lowing manner: 

E=e  +  C\  R, 
or  ECl  =  eC\  +  CltB.  (III.) 

But  the  work  done  by  a  dynamo  can  be  ex- 
pressed by  the  product  of  its  electromotive  force 
and  the  current  it  generates,  and,  according  to 
Joule,  the  heat  generated  in  a  circuit  is  pro- 
portional to  the  square  of  the  current  passing 
through  it  and  to  its  resistance.  We  can  there- 
fore put 

W=E  d,  andHJ=  C\2R. 


Equation  (III.)  can  then  be  written 

TF=e  <?!  +  HJ. 
On  comparing  this  with  (I.)  we  get: 

e  Cl  =  w.  (IV.) 

Or  substituting  the  value  of  C\  found  in 
equation  (II.), 

(E-e) 

w=e-  (IVa.) 

R 

or  the  work  done  by  the  motor  is  equal  to  the 
product  of  the  current  flowing  through  the  cir- 
cuit and  the  counter  electromotive  force  the 
motor  has  set  up. 

Referring  to  (II.),  we  find  that  if  E  and  R  be 
constant,  C  l  is  a  function  of  e,  for  any  change 
of  e  produces  a  change  of  C\.  Now,  as  e  d  is 
the  expression  for  the  work  done  by  the  motor, 


the  question  is,  for  what  current  will  e  Ct  be  a 
maximum?  To  find  this  maximum,  we  will 
write  (III.): 

and  employing  the  differential  calculus  for  the 
sake  of  brevity  we  get  by  placing  the  first  dif- 
ferential coefficient  equal  to  zero: 

d  e  C*! 

-  =  E—  2RCl=0, 
dd 

or  E=2Rd; 

but,  according  to  (L),  E=  R  C, 
C 
2  ' 

E  —  e        C 
=  ~^"' 
1  1 


therefore 
and  as 


2 


2 


E. 


That  is,  if  the  counter  electromotive  force  is 
such  that  the  current  flowing  through  the  cir- 
cuit is  just  one-half  of  the  current  which  would 
flow  through  it  if  the  motor  did  no  work,  the 
motor  will  be  doing  most  work  for  unit  time; 

C 

for  any  other  current  larger  or  smaller  than  — 

2 

the  amount  of  work  done  within  unit  time  will 
be  less. 

This  law,  generally  called  the  law  of  maximum 
activity,  was  discovered  by  Jacobi.  Although 
as  we  have  pointed  out  in  a  previous  chapter 
it  has  nothing  ivhatever  to  do  with  the  efficiency 
of  transmission,  it  has  often  been  mistaken  for 
the  law  governing  the  latter;  and  as  in  case  of 
maximum  activity  the  efficiency  of  transmis- 
sion is  50  per  cent.,  it  has  been  said  that  the 
highest  efficiency  of  the  system  is  only  50  per 
cent.  This  is  entirely  wrong,  as  the  efficiency 
can  be  made  as  high  as  one  likes.  This  will  be 
seen  later  on. 

Jacobi's  law  can  easily  be  proved  by  an  exam- 
ple. Let  £=100;  #=10;  then  (7=10,  and 
for  Ci  =  5,  e  =  50 ;  as  deduced  from  eq.  (II.) 


34 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


the  work  done  by  the  generator  is  E  d  =  500 
watts,  the  work  done  by  the  mptor  is  e  Cl  = 
250.  If  d  =  6,  then  from  (II.) 

E  —  e  =  R  d, 

or  100  —  e  =  60;  therefore,  e  =  40; 

E  d  =  COO,  e  d  =  240. 

If  d  =  4,  e  =  100  —  40  =  60, 

and  E  d  =  400,  e  d  =  240. 

(This  also  proves  what  has  been  said  about 

250       1 

the  efficiency,  as  in  the  first  case  y  =  —  =  -; 

500       2 
240       2 
in  the  second  »/  =  —  =  -;  and  in  the  last  case 

600       5 
240       3 

'/  =  —  =  -.)     The  Greek  letter  >/  stands  for  the 
400       5 

efficiency  of  transmission. 

In  his  work  on  dynamo -electric  machinery, 
Prof.  S.  P.  Thompson  has  given  diagrams  to 
show  this  law  graphically.  Our  equation  (II.)  is 

E—  e 


and*  E  d 

we  can  then  write 


R 
,.  e 


E  (E  —  e) 
W  = and  w 


(E-e) 


R  R 

and  as  R  is  a  constant  we  get  the  relative  values, 

E  (E  —  e)  and  e  (E  —  e). 

A J D 


B  H 

FIG.  40. 

Let  us  now  construct  a  square  at  A  B  C  D, 
Fig.  40,  the  side  of  which  is  equal  to  E,  and 
measure  out  from  the  point  B  the  counter  elec- 
tromotive force  e  =  B  F,  draw  F  K  parallel  to 
B  C  and  through  the  point  G,  in  which  F  K  in- 
tersects the  diagonal  B  D,  draw  J  H  parallel  to 
B  A.  The  rectangle  A  F  K  D  will  now  repre- 


sent the  work  done  by  the  generator,  as  A  F= 
E  —  e  and  F  K  =  E,  and  the  rectangle  G  H  C 
K  represents  the  work  absorbed  by  the  motor, 
as  G  H  =  e  and  H  (7=  E  —  e. 


11. 


According  to  a  well-known  geometrical  law 
the  rectangle  G  H  C  K,  Fig.  41,  will  be  a  maxi- 

AB 

mum  for  G  B  =  G  Dj  then  BF — ;  that  is 

2 

E 
e  =  — ,  and  as  was  shown  above,  if  the  counter 

2 

electromotive  force  is  half  the  electromotive 
force,  the  current  passing  through  the  circuit  is 
one-half  of  the  current  which  would  pass  if  the 
motor  were  standing  still.  The  square  G  H  C 

K  representing  w  is 

I 

=  T     ' 
The  rectangle  A  F  K  D  represents  W  or 

AFKD=W=E(E  —  e)  =  —  E-=2w. 

2 

According  to  this  diagram,  then,  the  motor 
will  do  most  work  in  unit  time  when  the -coun- 
ter electromotive  force  is  one-half  of  the  elec- 
tromotive force,  the  current  at  the  same  time 
being  one-half  of  the  current  which  would  flow 
through  the  circuit  if  the  motor  was  standing 
still. 

As  we  pointed  out  before,  and  as  formulas  (I.), 
(II.),  (III.)  and  (IV.)  show,  not  all  the  work  put 
into  the  generator  will  be  recovered  through 
the  motor.  In  the  following, both  generator  and 
motor  are  still  assumed  to  be  perfect — that  is, 
transforming  energy  of  one  form  into  another 
without  loss.  Of  course,  in  practice  this  will 
not  be  the  case,  but  the  nature  and  amount  of 
such  losses  are  known  to  all  good  dynamo- 
makers,  who,  therefore,  also  know  by  what 
means  they  can  be  brought  down  to  the  lowest 
limit.  Moreover,  it  will  be  very  difficult,  if  not 


THE  ELECTRICAL  TRANSMISSION   OF  POWER. 


35 


even  quite  impossible,  to  give  formulas  cover- 
ing all  these  sources  of  loss.  But,  aside  from 
these  losses,  part  of  the  energy  is  lost  in  the 
circuit,  being  that  part  which  is  necessary  to 
force  the  current  through  the  circuit.  The  rest 
of  the  energy  will  appear  as  useful  work  in  the 
motor  (assumed  to  be  perfect).  Now,  the  effi- 
ciency of  any  system  is  the  ratio  of  the  useful 
work  to  that  spent  in  producing  it;  that  is,  if  ij 
stand  for  the  efficiency  of  transmission, 

w 

n  —  — ,  and  in  our  case 
W 

w       e  Ci 

H  =  —  =  — -;  that  is 
W     EC, 


E 


(V.) 


According  to  this  equation,  the  efficiency  of 
transmission  is  as  the  ratio  of  the  electromotive 
forces.  This  again  shows  that  Jacobi's  law  of 
maximum  activity  has  nothing  to  do  with  the 
efficiency.  The  counter  electromotive  force  e 
can  range  between  the  limits  e  =  0  and  e  =  E, 
at  the  same  time  y  will  range  between  »/  =  0 


and  T]  =  1.    If  e  =  0,  then  rt 


••  0  also;  if  e  =  —  E, 


then 


—  ;    if  e  = 


E,  then 


In  the 


first  case,  the  motor  will  be  doing  no  work,  as 
the  energy  put  into  the  generator  will  be  lost 
in  heating  the  wires  of  the  circuit.  With  e  the 
efficiency  will  gradually  rise,  and  at  the  same 
time  the  actual  work  got  out  of  the  motor  in 

E  ] 

unit  time  till  e  =  — ,  at  this  point »/  =  — ;  that 
&  "Z 

is,  half  the  energy  put  into  the  generator  is 
lost  as  heat  in  the  circuit;  the  other  half 

-rp 

appears  as  useful  work,  and  for  e  =  -'-  also, 

i>j 

the  motor  will  be  doing  most  work.  As  e 
continues  to  rise,  17  does  the  same,  but  at  the 
same  time  the  work  done  per  unit  time  sinks 
again,  till  e  =  E.  Now,  iy  =  1.  but  the  motor 
will  be  doing  no  work,  and  theoretically  the 
generator  ought  to  require  none  either;  but 
in  practice  this  is  impossible,  as  e  can  never 


rise  so  high  that  e  =  E.  The  cause  of  this  is  the 
resistance  of  the  circuit,  and,  of  course,  the 
mechanical  resistance  of  the  armature,  such  as 
friction,  etc.  In  practice,  it  is  difficult  to  meas- 
ure the  counter  electromotive  force  e  (e  must 
not  be  confounded  with  the  difference  of  poten- 
tial at  the  terminals  of  the  motor);  it  is  more 
convenient  to  measure  the  current  flowing 
through  the  circuit  and  the  difference  of  poten- 
tials at  the  terminals  of  the  generator,  and, 
knowing  the  resistance  of  the  generator  and 
the  other  part  of  the  circuit,  the  electromotive 
force  of  the  generator  is  easily  found,  and  equa- 
tion (II.)  will  give  the  counter  electromotive 
force. 

These  relations  between  counter  electromo- 
tive force,  efficiency,  and  work  per  unit  time, 
can  very  easily  be  shown  graphically  with  the 
diagram  used  by  Thompson.  Let  A  B,  Fig.  40, 
again  be  equal  to  E,  F  B  =  e,  and  the  lines  F 
KJH  drawn  as  before;  then,  E  being  constant: 


G  H  C  K  =  e  (E  —  e) 


w. 


The  efficiency  of  transmission  will  then  be  as 
the  ratio  of  these  rectangles,  and  the  work  lost 
in  heating  the  circuit  will  be  represented  by 
JGKD,asAFGJis  equal  to  G  H  C  K. 


H  C 

FIG.  42. 

This  diagram,  therefore,  represents  a  case  in 
which  either  the  load  put  on  the  motor  is  too 
large  or  the  armature  not  properly  geared  to 
the  rest  of  the  working  parts  (in  an  electric 
locomotive,  to  the  wheels).  The  result  is  that 
the  armature  of  the  motor  cannot  move  with 
the  necessary  speed,  and  therefore  the  counter 
electromotive  force  is  very  low.  Fig.  42  is  the 
diagram  of  another  case;  A  B  again  is  equal  to 
E,  B  F  =  e.  The  work  spent  in  the  generator 
is.  therefore,  again  represented  by  the  rectangle 
A  F  D  K,  and  the  useful  work  by  G  H  C  K.  It 
is  easy  to  see  that  in  this  case  the  efficiency 


36 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


represented  by  the  ratio  of  the  two  rectangles 
is  far  superior  to  that  represented  by  Fig.  40. 
Whereas  in  Fig.  40  F  B  is  J  of  A  B  (i.  e.,E  =  3e), 
and  in  consequence  rectangle  OH  C  K  is  one- 
third  of  A  F  K  D,  the  efficiency  being  therefore 
TI  =  J,  in  Fig.  42  F  B  is  two-thirds  of  A  B  (that 
is,  2  E  =  3e),  and,  therefore,  rectangle  G  H  C  K 
is  f  of  rectangle  A  F  K  D,  making  the  effi- 
ciency i]  =  §.  In  this  case,  therefore,  although 
only  half  the  work  has  been  put  on  the  genera- 
tor, the  motor  is  doing  exactly  the  same  amount 
of  work  as  in  the  case  represented  by  Fig.  40. 
In  the  expression  for  the  efficiency 


"T 

there  is  no  term  representing  the  resistance  R. 
This  proves  clearly  that  theoretically  there  is  no 
limit  for  this  system  of  transmission,  and  that  the 
resistance  of  the  circuit,  or,  wliat  amounts  to  the 
same  thing,  the  distance  between  the  two 

e 

stations,  may  be  ever  so  large  ;  so  long  as  —  is 

E 

kept  constant,  the  efficiency  will  always  be  the 
same.  In  practice,  of  course,  a  limit  exists,  be- 
cause if  we  make  R  larger,  keeping  E  and  (in 
order  to  have  the  same  efficiency)  e  constant,  a 
smaller  current  would  flow  through  the  circuit, 
as  will  be  seen  by  referring  to  equation  (II.) 
This  equation  may  be  written 


E  and  e  being  the  same,  E  —  e  is  constant; 
altering  R,  therefore,  will  also  alter  d.  The 
result  is,  that  E  (7j  would  be  smaller  than  be- 
fore, and,  consequently,  if  the  resistance  is 
made  larger,  the  electromotive  forces  will  also 
have  to  be  increased. 

Again,  if  we  keep  the  resistance  constant, 
but  alter  the  electromotive  forces,  keeping  E— 
e  constant,  then,  according  to  equation  (II.)  the 
current  Ci  will  be  constant  too.  In  equation 
(III.)  the  term  R  CV  represents  the  amount  of 
energy  lost  as  heat  in  the  circuit,  and  as  it  only 
involves  R  and  C\,  it  follows  that  if  these  re- 
main the  same,  the  former  will  not  vary  with 
the  varying  electromotive  forces.  But,  on  the 
other  hand,  making  E  and  e  larger  also  makes 
the  amount  of  energy  transmitted  and  the 
amount  transformed  into  useful  work  larger. 
Fig.  43  shows  this  graphically. 


On  comparing  it  with  Fig.  42,  it  will  be  found 
that  J  G  K  D,  representing  the  heat  wasted,  is 
the  same  in  both  cases,  but  the  rectangles 
A  F KD  and  H  G  K  C  are  larger  in  Fig.  43 
than  in  Fig.  42.  More  energy  has,  therefore, 
been  transmitted;  but  as  the  losses  are  the 
same,  the  efficiency  in  the  case  represented  by 
Fig.  43  is  larger  than  in  that  represented  by 


FIG.  43. 

Fig.  42.  The  amount  of  energy,  therefore,  that 
can  be  transmitted  over  a  circuit  having  a  given 
resistance  is  again  theoretically  without  limit, 
and  the  larger  the  amount  of  energy  trans- 
mitted the  larger  will  be  the  efficiency  of  trans- 
mission, if  E  —  e  is  kept  constant. 

Let  E,  for  example,  be  200  volts,  e  =  150  volts, 
and  R  =  10  ohms; 
then  E  —  e  =  50 


and 


200—150 

Cl    =  -      —  =  5  amperes. 
10 


The  amount  of  energy  put  into  the  generator  ia 

JF=  E  d  =  1000  watts; 
the  useful  work  is 

^•  =  6(7!=  750  watts; 
energy  lost  as  heat, 

H  J=  R  C,2  =  250  watts; 
the  efficiency  is 


e        150        3 

E       200        4' 
Now  let  E  =  400  volts,  e  =  350  volts,  and 


R  again  =  10  ohms; 
then 

E  —  e 


50. 


400—350 

C  i  =  —        -  =  5  amperes. 
10 


THE  ELECTRICAL  TRANSMISSION  OP  POWER. 


37 


and 


W=  E  Cl  =  2000  watts. 
w  =  e  Ci  =  1750  watts. 
HJ=RC^=  250  watts, 
e        350        7 


E 


400 


8 


We  have  now  put  into  the  generator  double 
the  amount  of  energy;  of  this  the  same  amount 
is  lost  in  heating  the  circuit,  and  the  efficiency 
has  risen  from  f  to  J. 

This  clearly  shows  that  it  is  always  more 
economical  to  use  small  currents  with  high  elec- 
tromotive forces,  the  more  so  since  the  higher 
the  electromotive  force  the  greater  the  resist- 
ance can  be  made  without  altering  the  effi- 
ciency, and  the  less  will  be  the  cost  of  the 
circuit. 

Up  to  the  present  we  have  assumed  that  only 
that  amount  of  energy  is  lost  which  appears  as 
heat  in  the  circuit;  but  there  is  another  source 
of  loss  due  to  the  leakage  of  current  between 
the  two  conductors.  With  currents  of  low  ten- 
sion this  is  not  preceptible,  as  the  insulation  can 
easily  be  made  perfect;  but  on  long  lines  and 
with  high  electromotive  forces  this  loss  may  be 
so  large  as  to  lower  the  efficiency  somewhat. 

It  will  now  be  necessary  to  say  a  few  words 
about  the  resistance  and  efficiency  of  the  dif- 
ferent parts  of  the  circuit.  The  circuit  consists 
of  three  different  parts,  and  they  are:  the  gen- 
erator, the  conductors,  and  the  motor.  Letting 
r,  stand  for  the  resistance  of  the  generator,  rt 
for  that  of  the  conductors,  and  r3  for  that  of 
the  motor,  then  the  resistance  of  the  circuit 
will  be: 

E  =  ?-!  +  r2  +  rs. 

Let  /i  L  I,  stand  for  the  losses  of  energy  in 
these  different  parts,  then  we  will  have: 

/ r<  2  r 

«1  =     I'l     Mi 

; n  2  - 

J2 Oi       I  2» 

/.  =  Ci1  rs, 

and  the  efficiency  will  be:  TJ  =  17,  x  %  X  %,  and 
ECi—d*^       E—C.r, 


EC, 


E 


E  d  — 


i\  —  C,  2  r2    E  —  Ci  t\  —  (7,  r2 


EC1-  (Vr,  E—CiTi 

E  G\— (7,  ">-,—<?,  2r2—CVr3    E—C^—Cir.-dr,. 


But  C\  i\  is  the  electromotive  force  necessary 
to  force  a  current  Cl  through  a  resistance  n ; 
E  —  Ci  i\  will  therefore  be  the  difference  of  po- 
tential at  the  terminals  of  the  generator,  and 
for  similar  reasons  E —  Ci  rt  —  Cf1r2  will  be  that 
at  the  end  of  the  conductors  or  terminals  of  the 
motor.  On  the  other  hand,  Ci  r3  gives  the  loss 
of  electromotive  force  due  to  the  resistance  of 
the  wire  on  the  motor,  but  the  electromotive 
force  at  this  end  of  the  circuit  has  already  been 
shown  to  be  equal  to  e,  and  if  e,  and  e2,  respect- 
ively, stand  for  the  other  two,  then  we  haver 


and 


Ci        e2        e        e 
—  x  —  x  —  =  — . 
E       d       ea       E 


E  C,  —  C,  2  r,—  C,  "  r2 


—C^  —C,  r2 


We  have  seen  from  equation  (V.)  that  the  effi- 
ciency of  transmission  is  as  the  ratio  of  the 
electromotive  forces  of  the  generator  and  re- 

e 

ceiver  i.  e., — .     As  this  expression  does  not  con- 
E 

tain  the  factor  of  resistance  R,  of  the  line  or 
machines,  M.  Deprez  was  led  to  promulgate  the 
theory  that  in  the  electrical  transmission  of 
energy  the  efficiency  is  independent  of  the  dis- 
tance of  transmission.  This  theory,  first  started 
in  March,  1880,  has  provoked  considerable  dis- 
cussion. It  means,  in  effect,  that  we  can  make 
the  distance,  and  hence  the  resistance  of  the 
line,  whatever  we  please  without  loss  of  effi- 
ciency. 

We  cannot  here  enter  into  a  full  discussion  of 
this  view,  but  we  may  say  briefly,  that  as  a 
theory,  pure  and  simple,  the  proposition  is  cor- 
rect, as  was  developed  in  the  preceding  pages. 
But  there  are  practical  difficulties  which  pre- 
vent its  realization,  and  it  would  be  dangerous 
to  apply  it  in  the  calculations  of  a  working  en- 
terprise. It  is  evident  that  the  quantity  of  heat 
generated  in  a  conductor  by  the  electric  current 
ought  to  increase  with  the  length  of  the  wire, 
and  hence  the  loss  would  increase.  On  the 
other  hand,  M.  Deprez  argues  that  the  pro- 
duction of  heat  varies  as  the  square  of  the  in- 
tensity of  the  current,  and  that  the  latter  is 
diminished  by  an  increase  of  the  length  of  the 
line. 

The  question  suggests  itself:  How  can  the 
evil  effects  of  increased  distance  be  obviated? 


38 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


We  have  seen  by  equation  (IV.  a)  that  the 
useful  work  of  the  motor  is  equal 

e  (E—e) 
R 

This  equation  shows  that  there  are  two  ways 
of  overcoming  the  difficulties  of  long  distance 
transmission  of  a  given  power.  Thus  we  can 
either  diminish  R,  the  resistance  of  the  con- 
ductor, by  increasing  its  diameter;  or  we  can 
increase  the  relative  electromotive  forces  of 
the  machines. 

The  first  method,  that  of  increasing  the  size 
of  the  conductor,  was  first  proposed  by  M. 
Maurice  Levy,  in  February,  1882,  in  a  note  to 
the  French  Academy  of  Sciences,  wherein  he 
says  that  "the  resistance  of  the  exterior  cir- 
cuit can  be  made  very  small,  even  for  long  dis- 
tances, by  employing  a  very  large  wire." 
Evidently,  this  would  be  an  easy  way  out  of 
the  difficulty  if  it  were  not  for  the  fact  that  any 
increase  in  the  size  of  the  conductor  means 
increased  cost,  and  hence,  starting  from  an 
economical  standpoint,  we  soon  reach  a  limit  in 
the  size  of  conductor  that  can  be  used. 

The  second  method  of  overcoming  the  diffi- 
culties of  long  distance  transmission,  as  we 
have  seen  above,  consists  in  increasing  the 
electromotive  forces  of  the  machines.  This  is 
the  method  developed  by  M.  Marcel  Deprez  and 
consists  in  employing  high  tension  currents. 
According  to  M.  Deprez,  in  order  to  obtain  the 
same  useful  work,  whatever  be  the  length  of 
the  line,  it  suffices  simply  to  vary  the  electro- 
motive forces  of  the  machine  proportionally  to 
the  square  root  of  the  resistance  of  the  circuit. 
In  other  words,  if,  as  before,  R  represents  the 
resistance  of  the  circuit,  and  E  and  e,  respect- 
ively, the  electromotive  forces  of  the  machines, 
and  in  such  a  circuit  we  obtain  useful  work  at 
the  motor  w,  then,  in  order  to  obtain  the  same 
amount  of  work  with  other  values,  R1,  E1,  e1,  it 
is  necessary  to  make  the  new  values  E1  and  e1 
such,  that  they  will  satisfy  the  following  equa- 
tions: 


Or  if  we  let  w.-1  represent  the  work  produced 
in  the  second  case,  we  have: 


E1 
E 


(VI.) 


(VII.) 


w  = 


e(E-e) 
R 


A" 

Substituting  now  in  the  latter  equation  the 
values  of  E1  and  e  developed  from  equations 
(VI.)  and  (VII.),  we  get: 


w 


R 


e  (E  —  e) 
R 


=  w. 


Before  describing  the  experiments  made  by 
M.  Deprez  to  demonstrate  this  theory  we  must 
allude  to  another  form  in  which  according  to 
M.  Deprez  the  efficiency  of  transmission  can  he 
expressed;  and  that  is,  that  the  efficiency  is 
equal  to  the  ratio  of  the  speeds  respectively  of 
generator  and  motor.  Calling  N  the  former, 
and  n  the  latter,  the  efficiency  would  be  ex- 
pressed by, 

n 

N 

This,  of  course,  assumes  that  the  two  ma- 
chines are  identical,  that  the  magnetic  field  and 
the  current  are  the  same  in  intensities  in  both, 
and  hence  that  the  electromotive  forces  de- 
veloped are  proportional  to  the  speeds  of  the 
armatures.  This,  however,  is  not  the  case  if 
there  is  any  leakage  along  the  line,  for  then  not 
all  the  current  developed  by  the  generator 
passes  through  the  motor.  Moreover,  as  Prof. 
S.  P.  Thompson  points  out,  when  there  are  re- 
sistances in  the  line,  the  ratio  of  the  electromo- 
tive forces  of  the  machines  is  not  the  same  as 
the  ratio  of  the  two  differences  of  potentials,  as 
measured  between  the  terminals  of  the  ma- 
chines. 

Further,  even  though  the  current  running 
through  the  armatures  and  field  magnets  in  the 
generator  which  creates  the  current,  and  in  the 
motor  which  utilizes  the  current,  be  absolutely 


THE  ELECTRICAL  TRANSMISSION  OF  POWER. 


39 


identical,  the  intensities  of  the  magnetic  fields 
of  the  two  machines  are  not  equal, — even 
though  the  machines  be  absolutely  alike  in 
build;  because  the  reaction  between  the  arma- 
ture and  the  field  magnet  is  entirely  different 
in  the  dynamo  used  as  a  motor  from  that  in  the 
dynamo  which  is  being  used  as  a  generator. 

As  we  have  stated  above,  M.  Deprez,  by  em- 
ploying high  electromotive  forces,  seeks  to  di- 
minish the  current,  and  thus  to  diminish  the 
heat  which  it  generates  in  the  conductor  to 
such  an  extent  that  it  shall  be  inappreciable. 

His  experiments  to  demonstrate  the  truth  of 
his  theory  are  very  interesting,  and  of  great 
value  from  a  scientific  standpoint. 

The  first  real  long  distance  transmission  was 
undertaken  by  M.  Deprez  at  the  Munich  Elec- 
trical Exhibition  of  1882,  with  two  Gramme 
machines.  These  were  placed  respectively  at 
Munich  and  at  Miesbach,  a  distance  apart  of  57 
kilometres  (37  miles).  They  were  connected 
by  an  ordinary  iron  telegraph  wire;  4J  mm.  in 
diameter,  and  constituted  a  complete  metallic 
circuit  114  kilometres  (74  miles)  in  length.  The 
resistance  of  the  line  measured  950.2  ohms;  that 
of  the  generating  machine  at  Miesbach  453.4 
ohms;  and  that  of  the  motor  at  Munich  453.4. 

The  generator  was  placed  in  the  workshop  of 
Herr  Fohr,  and  appeared  as  shown  in  the  illus- 
tration, Fig.  44.  The  motor  was  placed  in  the 
Munich  Crystal  Palace,  and  was  belted  to  a 
centrifugal  pump  which  fed  a  cascade  nearly 
three  metres  in  height,  as  illustrated  in  Fig.  45. 
The  measurements  taken  by  the  committee 
were  as  follows: 

Speed  of  generator  at  Miesbach,  .  .  .  1611  revolutions. 
Intensity  of  current  at  "  ....  0.519  ampere. 

Speed  of  motor  at  Munich, 752   revolutions. 

Difference  of  potential  at  terminals  of  motor,  8.30  volts. 
Work  measured  by  brake  at  motor,       .     .     0.25  II.  P. 

From  these  data  the  following  values  were 
calculated: 

Difference  of  potential  at  terminals  of  gen- 
erator  1343  volts. 

Total  electrical  energy  at  Miesbach,     .     .     1.13  H.  P. 
Total  electrical  energy  at  Munich,   .     .     .     0.433  H.  P. 
Electrical  efficiency 38.9  per  cent. 

It  will  be  understood  here  that  this  efficiency 
is  not  the  absolute  or  commercial  efficiency,  but 
the  electrical  alone.  We  must  explain  this  by 
an  example.  If,  for  instance,  in  the  above 
case,  all  the  power  applied  to  the  generator  had 


been  converted  into  electrical  energy,  or,  in 
other  words,  if  the  generator  were  a  perfect 
machine;  and  if  the  motor  had  converted  all 
the  electricity  into  useful  work,  then  the  effi- 
ciency would  have  been  that  given,  viz.,  38.9 
per  cent.  The  absolute  efficiency  of  a  system 
is  the  ratio  of  the  power  applied  to  the  genera- 
tor to  that  obtained  from  the  motor.  It  thus 
includes  not  only  the  electrical  efficiency  but 
that  also  of  the  motor  and  generator,  as  con- 


Fio.  44. — DEPHKZ  GENERATOR- AT  MIKSBACH. 

verters  of  energy.  Thus,  in  the  above  experi- 
ment, while  the  electrical  efficiency  was  38.9 
per  cent.,  the  absolute  efficiency  must  have  been 
less.  Exactly  how  much  less  this  was  we  have 
no  means  of  telling,  because  the  power  applied 
to  the  generator  at  Miesbach  was  not  meas- 
ured. But  if  we  assume  the  efficiencies  of  the 
motor  and  generator  each  to  have  been  85  per 
cent.,  we  would  have  for  the  absolute  efficiency 
of  the  transmission  0.85  x  0.85  x  38.9  or  about 
28  per  cent. 

M.  Deprez,  however,  did  not  rest  contented 
with  these  experiments,  but  followed  them  up 


40 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


FIG.  45.— DEPREZ  INSTALLATION  AT  THE  MUNICH  EXPOSITION,  1882. 


THE  ELECTRICAL  TRANSMISSION  OF  POWER. 


41 


by  others  in  1883  from  the  depot  of  the  Chemin 
deFer  du  Nord,  Paris,  to  La  Chapelle,  a  distance 
of  8,500  metres — about  5J  miles;  and  another 
from  Vizille  to  Grenoble,  a  distance  of  14  kilo- 
metres (7J  miles).  The  generator  used  is  shown 
in  Fig  46.  The  most  recent,  and  perhaps  the 
most  important,  of  M.  Deprez's  experiments  in 
long  distance  transmission  was  undertaken  in 
October,  1885,  and  the  object  aimed  at  was  to 
demonstrate  the  practical  application  and  dis- 
tribution of  power  transmitted  over  a  long  dis- 
tance. For  this  purpose  the  apparatus  was 


metres  from  each  other.  Each  possessed,  like 
the  generator  described  below,  two  rings;  they 
were  each  0.58  metre  in  exterior  diameter  and 
had  an  electric  resistance  of  18  ohms. 

Our  illustration,  Fig.  47,  shows  one  of  the 
generators. 

In  the  generating  machine  the  field  is  pro- 
duced by  8  electro-magnets  of  horseshoe  form, 
and  the  pole  pieces  embrace  the  armatures  over 
very  nearly  their  entire  circumference.  The 
field  is  excited  by  a  separate  dynamo,  and  the 
current  is  passed  through  the  different  electro- 


FIG.  46. — DKPRKZ  GENERATOR  AT  THE  CHEMIN  DE  PER  DU  NOUD,  PARIS,  1883. 


«.ritende<l  to  operate  electric  light  machines,  to 
drive  pumps  and  to  run  machine  tools  at  the 
company's  workshops. 

The  distance  from  Paris  to  Creil,  between 
which  two  points  the  line  extended,  is  50  kilo- 
metres (34  miles),  making  a  total  length  of 
conductor  of  68  miles.  The  line  consisted  of  a 
lead-incased  insulated  copper  wire  5  mm.  in 
diameter,  and  its  resistance  was  100  ohms. 

The  generating  machine  was  situated  at 
Creil.  It  had  two  rings  revolving  in  two  dis- 
tinct magnetic  fields,  each  composed  of  eight 
electro-magnets.  Each  armature  had  a  resist- 
ance of  16.5  ohms. 

The  current  produced  by  this  machine  was 
utilized  at  La  Chapelle,  near  Paris,  by  two  re- 
ceiving machines,  situated  at  some  hundreds  of 


magnets  so  that  a  north  pole  on  one  side  of 
the  armature  is  opposite  a  south  pole  on  the 
other. 

The  total  weight  of  each  of  the  electro-mag- 
nets is  485  kilogrammes.  They  are  wound  with 
copper  wire  2£  millimetres  in  diameter.  The 
wire  is  covered  with  two  layers  of  silk,  one  of 
cotton,  and  finally  with  a  layer  of  shellac.  The 
total  length  of  wire  wound  on  the  magnets  is 
56,496  metres.  The  winding  is  done  in  sections, 
each  having  the  form  of  a  flat  ring.  Each  sec- 
tion is  composed  of  11  layers  of  25  convolutions 
each.  The  core  of  each  electro-magnet  carries 
12  of  these  sections,  and  the  ends  of  the  wires 
are  led  to  the  terminal  boards,  so  that  they  can 
be  coupled  up  in  any  manner  desired.  The  re- 
sistance of  each  section  is  1.06  ohm,  and  the 


42 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


total  resistance  of  the  magnets  grouped  in  se- 
ries would  be  203.52  ohms. 

The  radius  of  the  pole  pieces  is  710  mm.  and 
their  thickness  120  mm.  All  the  pole  pieces 
on  the  same  side  of  a  horizontal  plane  passing 
through  the  shaft  are  in  magnetic  communica- 
tion with  one  another. 


wire  is  2J  millimetres  in  diameter  and  insulated 
in  the  same  way  as  the  magnet  wire.  The 
following  are  the  principal  dimensions  and 
weights: 

No.  of  sections  per  segment, 21 

Total  No.  of  sections 231 

Length  of  wire  per  section, 52  metres. 


FIG.  47. — DEPREZ  GENERATOR  AT  CREIL,  1885. 


The  armature  is  wound  in  sections  after  the 
Pacinotti  type,  which  presents  the  characteris- 
tic that  it  consists  of  a  series  of  sections  which 
can  be  removed  and  replaced  in  case  of  acci- 
dent. The  armature  frame  consists  of  a  hub 
with  a  spider  at  each  end.  The  sections  are 
separately  wound  on  soft  iron  cores  and  are 
then  bolted  to  and  between  two  opposite  spokes 
on  the  shaft.  Each  segment  of  the  armature 
winding  is  divided  into  21  sections,  and  the 


Total  length  of  wire  wound  on  the  ring,      .       12,01 2  metres. 

Diameter,  external,        1,386  mm. 

"          internal,        1,070     " 

Thickness  of  wire  coil  above  core,     ....  83     " 

«          "      «       "     below     " 45     '• 

Length  parallel  to  axis G06     " 

Weight  of  wire,  including  insul , 552.5   kg. 

In  a  preliminary  trial  this  armature  gen- 
erated an  electromotive  force  of  16  volts  per  revo- 
lution per  minute.  Each  armature  has  its  own 


THE   ELECTRICAL  TRANSMISSION   OF   POWER. 


43 


commutator  and  brushes,  the  latter  being  at- 
tached to  a  holder  movable  by  a  worm  wheel 
which  gears  with  it. 

In  a  note  presented  to  the  French  Academy 
of  Sciences,  M.  Deprez  gave  the  results  of  ex- 
periments undertaken  with  these  machines, 
and  they  are  quoted  below: 

FIRST  EXPERIMENT. 

Generator.    Receiver. 

Speed  in  rev.  per  minute, 190  218 

Electromotive  force,  direct  or  inverse,    5469  volts  4242  volts. 

Intensity  of  current, 7.21  amp.  7.21   amp. 

Work  in  field  magnets  (in  horse  power)  9  20  3.75 

Electrical  work  (in  horse  power)  .     .  53.59          41.44 
Mechanical  work  measured  with  the 

dynamometer  or  the  brake  (horse 

power) 62.10          35.10 

EFFICIENCY. 

Electrical, 77    per  cent. 

Commercial  or  mechanical 47.7       " 

SECOND  EXPERIMENT. 

Generator.      Receiver. 

Speed  per  minute, 170  277 

Electromotive  force, 5717  volts.  4441  volts. 

Intensity  of  current, 7.20  amp.   7.20  amp. 

Work  in  field  magnets, 10.30  H.  P.  3.80  II.  P. 

Electrical  work, 55  90      "      43.4      " 

Mechanical  work  (measured  with  the 

dynamometer  or  the  brake),  ...       61       "         40      " 

EFFICIENCY. 

Electrical, 78  per  cent. 

Commercial  or  mechanical, 53.4     " 

These  results  which  showed  that  40  H.  P.  had 
been  transmitted  with  a  commercial  efficiency 
of  about  50  per  cent,  have  been  variously  criti- 
cised. In  the  first  place  the  generator  and 
motor  were  placed  side  by  side,  the  line  being 
in  a  loop  around  them.  Evidently  if  leakage 
occurred  on  the  line  it  would  be  the  same  in 
effect  as  if  the  line  were  shortened.  Again,  the 
power  required  to  magnetize  the  field  magnets, 
which  were  independently  excited,  is  not  taken 
into  account,  so  that  the  mechanical  efficiency 
cannot  be  taken  as  the  true  one. 

It  will  be  noted  that  M.  Deprez  uses  an 
electromotive  force  as  high  as  6,000  volts, 
which  he  reached  on  another  occasion,  and 
which  of  necessity  requires  an  extraordinary 
degree  of  insulation,  both  on  the  line  and  in 
the  machines.  But  in  spite  of  the  precautions 
he  had  taken  he  met  with  a  mishap  which  de- 


stroyed one  of  his  machines,  and  which  was 
caused,  no  doubt,  by  the  giving  way  of  the  in- 
sulation. 

As  it  is  only  by  the  employment  of  very  high 
electromotive  force  that  we  can  approach  to  a 
realization  of  M.  Deprez's  theory  of  electric 
transmission,  the  question  naturally  suggests 
itself:  What  will  be  the  ultimate  result  of  M. 
Deprez's  experiments,  taking  into  account 
existing  conditions? 

In  considering  this  question.  Mr.  W.  J.  John- 
ston in  a  paper  read  before  the  National  Electric 
Light  Convention  at  Baltimore,  in  February, 
188G,  reviews  the  situation  in  the  following 
forcible  remarks.  He  says: 

"That  power  can  be  transmitted  we  all  know. 
Given,  then,  that  M.  Deprez  succeeds  in  his 
attempt,  will  that  alter  the  present  condition  of 
affairs,  as  regards  the  economical  side  of  the 
problem?  The  cost  of  his  installation,  and  the 
interest  thereon,  will  far  exceed  the  similar 
items,  including  maintenance  of  a  steam  plant 
of  equal  power,  at  the  place  where  it  is  wanted. 
Yet,  paradoxical  as  it  may  seem,  the  great 
problem  to  be  solved  is  not  the  transmission  of 
100  horse  power,  but  of  thousands  and  tens  of 
thousands.  Now,  this  can  only  be  done  in  one 
of  two  ways;  by  increasing  either  the  electro- 
motive force  or  the  current.  If  the  latter  plan 
is  pursued,  an  increase  in  the  size  of  conductor 
must  necessarily  follow  with  its  attending  cost, 
and  this  is  feasible,  but  not  at  present  economical. 
On  the  other  hand,  can  the  electromotive  force 
be  increased  much  beyond  the  limit  which  M. 
Deprez  is  now  using?  Dynamo  builders  know 
how  perfect  the  insulation  of  the  armature 
must  be,  and  how  little  it  requires  to  burn  one 
out  under  but  slightly  abnormal  conditions. 
Those  especially  who  have  experimented  with 
the  40,  50  and  CO  arc  light  machines  using  two 
or  three  thousand  volts,  have  possibly,  on  more 
than  one  occasion,  witnessed  an  effect  in  the 
armature  as  if  the  latter  had  been  struck  by 
lightning.  This  effect  is  one  entirely  different 
from  what  would  be  produced  in  a  machine  in 
which  the  armature  has  been  actually  burned 
out  by  a  heating  of  the  wires  from  too  great  a 
current.  The  break  resembles  that  made  by  a 
disruptive  discharge,  an  actual  spark;  and  M. 
Deprez  has  already  experienced  one  of  these 
mishaps,  in  spite  of  the  fact  that  he  uses  two 
layers  of  silk  and  one  of  cotton  for  the  insula- 
tion. The  fact  is,  a  dynamo  of  large  power 


44 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


which  is  subjected  of  necessity  to  rough  in- 
fluences cannot  be  made  to  generate  currents  of 
very  high  electromotive  force  for  a  continued 
service,  on  account  of  the  impossibility  of  se- 
curing sufficient  insulation.  The  problem  bears 
considerable  analogy  to  that  of  the  steam  en- 
gine. The  use  of  high  pressure  steam  of,  say, 
500  or  1,000  pounds  to  the  square  inch,  would 
effect  great  economy,  but  it  is  materially  im- 
practicable, as  the  cost  of  building  engines  and 
boilers  to  withstand  these  pressures  would  be 
out  of  proportion  to  the  benefits  derived,  and 
no  working  joint  could  withstand  the  pressure. 

"  For  the  reasons  given  above  it  would  appear 
that  as  regards  long-distance  large  power  trans- 
missions, substantial  improvements  are  re- 
quired before  it  can  become  a  commercial  suc- 
cess." 

We  have  dwelt  at  length  upon  the  long-dis- 
tance transmission  experiments  of  M.  Deprez,— 
who  indeed  stands  honorably  first  and  alone  in 
this  field  thus  far, — for  the  reason  that  his  work 
presents  good  ground  for  study  and  develop- 
ment. M.  Deprez's  theory  while  correct  in 
principle,  cannot,  unfortunately,  be  realized  in 
practice  to  a  commercial  extent,  under  the  con- 
ditions prevailing  at  the  present  time. 

Leaving  this  part  of  the  subject  which  is  still 
in  the  tentative  state,  and  directing  our  at- 
tention to  actual  successful  commercial  prac- 
tice, we  find  that  for  moderate  distances  large 
powers  can  be  transmitted  with  ease  and 
economy,  as  evidenced  by  the  numerous  appli- 
cations detailed  in  the  succeeding  chapters. 

The  time  will  soon  arrive,  in  fact  it  is  already 
upon  us,  when  electricity  will  be  distributed 
for  power  and  light  as  generally  as  gas  is  at 
present,  and  it  becomes  necessary  to  consider 
the  most  economical  method  of  distribution. 

The  problem  of  the  most  economical  section 
of  conductor  to  be  employed  in  a  power  distri- 
bution by  electricity  is  included  in  this  aspect 
of  the  question,  and  is  perhaps  one  of  the  most 
important  points.  In  discussing  it,  Mr.  Thomas 
W.  Rae,  C.  E.,  assumes  for  the  sake  of  an  ex- 
ample that  the  amount  of  power  to  be  circu- 
lated in  the  form  of  current  is  500  horse-power, 
the  length  of  the  circuit  4,000  yards,  or  2.27 
miles,  and  the  cross-section  of  the  copper  con- 
ductor 3.25  square  inches.  The  potential  of  the 
current  is  restricted  to  120  volts. 

The  current  equivalent  of  500  horse  power  be- 
ing 373,000  volt-amperes,  it  follows  that  the  theo- 


retical value  of  the  current  flowing  in  the  cir- 
cuit would  be  3,108  amperes. 

This,  however,  says  Mr.  Rae,  is  subject  to 
correction  for  the  loss  involved  in  the  conver- 
sion of  mechanical  work  into  current;  which  is 
due  to  the  frictional  and  electrical  resistances 
of  the  generating  dynamo.  It  will  be  prudent 
and  more  in  accord  with  other  conditions  of  the 
problem — to  be  stated  later — to  put  this  loss  at 
15  per  cent.,  and  consequently  there  may  be 
considered  to  be  a  current  of  2,042  amperes 
flowing  in  the  conductor. 

It  is  evident  that  the  flow  of  any  appreciable 
current  in  any  practicable  conductor  must 
evolve  heat.  If  a  uniform  temperature  of  con- 
ductor is  to  be  maintained,  this  development  of 
heat  must  be  got  rid  of  by  radiation  or  conduc- 
tion; or  it  becomes  cumulative  and  detrimental, 
by  creating  a  wasteful  resistance  in  the  circuit 
and,  in  the  case  of  insulated  conductors,  some- 
times destroying  the  insulating  medium. 

The  latter  class  of  conductor  would  seem  to 
offer  especial  difficulties,  and  the  problem  is  as 
yet  too  new  to  have  invited  much  investigation 
or  experiment.  While  it  is  undoubtedly  true 
that  the  best  dielectrics  are,  probably  without 
exception,  the  worst  conductors  of  heat  and  the 
rates  of  their  efficiency,  in  this  sense,  are 
practically  unknown,  it  has  also  been  experi- 
mentally demonstrated  that  insulated  conduc- 
tors have  even  less  tendency  to  augment 
temperature  under  the  passage  of  a  current 
than  bare  wires.  This  is  a  deduction  from 
laboratory  tests,  and  must  be  accepted  only 
within  proper  limits.  The  seeming  paradox 
vanishes  when  one  reflects  that  the  worst  possi- 
ble conductor  of  heat  is  dry  motionless  air,  and 
that  the  larger  periphery  of  the  insulated  wire 
radiates  the  greater  quantity  of  heat  in  the 
same  time.  The  result  would  be  reversed  if  the 
two  types  of  conductor  were  exposed  to  draughts 
of  wind;  but  the  instance  is  cited  to  show  that 
the  general  formulae  are  applicable  to  both 
classes.  Every  case,  however,  may  be  said  to 
be  a  special  case,  and  in  view  of  the  number- 
.less  and  unforeseeable  influences  affecting  the 
temperature  of  a  subterranean  conductor  two 
and  a  quarter  miles  long,  it  seems  almost  fini- 
cal to  be  calculating  the  effect  of  a  few  degrees 
due  to  current  resistance.  Nevertheless  the 
investigation  is  of  importance. 

It  is  presumable  that  a  conductor  buried  in 
homogeneous  earth  and  well  below  the  frost 


THE  ELECTRICAL  TRANSMISSION  OF  POWER. 


45 


line  would  retain  about  a  uniform  temperature 
all  the  year  round,  but  that  temperature  would 
depend  upon  the  nature  of  the  soil. 

It  would  naturally  be  one  thing  for  clay, 
another  for  sand,  and  another  for  rock;  and' 
none  of  these  could  be  known  except  by  experi- 
ment. In  all  probability,  a  conductor  of  any 
considerable  length  would  pass  through  all  va- 
rieties of  soil,  across  places  alternately  dry  and 
wet,  possibly  near  steam  pipes,  and  any  at- 
tempt to  assign  quantitative  temperature  to 
them  would  be  farcical.  In  such  circumstances, 
the  only  recourse  is  to  general  formula?,  as  fur- 
nishing—all things  considered  —  as  fair  an 
average  of  the  conflicting  influences  as  possible, 
and  one  of  Clark  and  Sabine  will  do  as  well  as 
any.  It  is 

0  =  0.24051?  Czt, 
in  which 

6  =  units  of  heat. 

R=  resistance  in  ohms. 
G=  current  in  amperes. 
t  =  time  of  flow  in  seconds. 

Since  the  current  in  this  case  is  practically 
continuous,  t  will  disappear,  and  the  factor  R 
must  be  deduced,  Clark  and  Sabine  again  fur- 
nishing the  means  with  their  formula 

1002.4 


w 

w  being  the  weight  in  pounds  of  a  statute  mile 
of  the  conductor  whose  resistance  is  sought. 

In  the  case  in  question  the  weight  of  a  statute 
mile  is  65,261  Ibs.,  and  its  resistance  at  60°  Fahr. 
consequently  .01530  ohm;  making  the  resistance 
of  the  entire  4,000  yards  .035  ohm. 

Carrying  out  the  operations  indicated  by  the 
formula,  it  will  be  found  that 

9  =  58,756; 

that  is  to  say,  the  given  current  will  develop  in 
the  given  conductor  so  many  units  of  heat. 

If  it  were  conceivable  that  the  substance  of 
the  conductor  was  water  and  weighed  just 
58,756  pounds,  this  would  mean  that  its  tem- 
perature would  be  raised  one  degree  Fahren- 
heit. But  its  material  is  copper,  whose  specific 
heat  is  .092  or — familiarly  speaking — which  re- 
quires but  .092  of  the  quantity  of  heat  that 
water  does  to  affect  its  temperature  equally; 
and  its  weight,  as  has  been  seen,  is  148,320 
pounds. 


Adapting  the  result  to  these  conditions,  it  will 
appear  that  the  conductor  under  consideration 
will  have  its  temperature  raised  by  the  current 
circulating  in  it,  only  4. 17°  Fahrenheit,  above 
what  it  would  be  if  out  of  circuit. 

This  increment  is  so  trivial  with  regard  to 
any  harmful  influence  it  might  exert  upon  the 
insulating  medium  used  with  the  conductor, 
that  search  must  be  made  in  other  directions 
for  the  reason  which  prescribes  its  seemingly 
excessive  size. 

Good  gutta  percha  will  endure  a  temperature 
of  120°  Fahr.  before  failing,  and  india  rubber 
300°  Fahr.  So  the  cause  is  probably  the  reduc- 
tion of  current,  and  consequently  of  merchant- 
able horse  power,  resulting  from  an  increase  of 
resistance  by  augmented  temperature. 

The  resistance  of  copper  increases  -fi^  of  one 
per  cent,  for  each  additional  degree  Fahrenheit 
of  temperature,  and  in  the  case  of  the  predi- 
cated current  and  conductor,  the  resistance  of 
the  latter  will  be  enhanced  but  -Pfo  of  one  per 
cent.  For  the  purposes  of  discussion,  the  loss 
of  current  due  to  this  augmented  resistance  will 
be  ignored  for  the  present.  To  estimate  the 
effect  of  such  increase  of  resistance  from  a 
financial  standpoint,  the  subjoined  method  is 
convenient. 

The  2,642  amperes  of  current  flowing  in  the 
conductor  are  subject  to  a  farther  diminution, 
before  they  appear  in  merchantable  shape, 
which  occurs  in  their  transformation  by  the 
converting  dynamos  into  horse  power. 

It  may  be  safely  taken  at  17  per  cent.;  which 
amounts  to  the  admission  that,  of  the  500  horse 
power  applied  to  the  generating  dynamos,  but 
70  per  cent,  may  be  counted  upon  as  returnable, 
in  the  same  form,  from  the  converting  dynamos. 
One  of  the  postulates  of  the  problem  is  that  at 
least  this  proportion  of  the  applied  mechanical 
power  should  be  recovered  after  having  under- 
gone all  its  transformations,  and  the  loss  has 
been  equally  divided — which  is  probably  as  fair 
an  allotment  as  possible — between  the  two  con- 
versions. 

There  should  be,  then,  350  horse  power  avail- 
able for  the  production  of  revenue;  but,  owing 
to  an  idiosyncrasy  of  electric  power,  there  is 
very  much  more.  An  instant's  reflection  will 
satisfy  one  that  where  an  amount  of  power  is 
distributed  among  a  number  of  consumers  for 
intermittent  use  the  chance  of  every  one's  desir- 
ing to  avail  of  his  power  at  the  same  instant  is 


46 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


infinitesimal,  and  experience,  as  far  as  it  goes, 
confirms  this.  The  character  of  the  work  done 
may  also  originate  compensating  influences  to 
the  same  end,  as  when  the  power-circuit  in- 
cludes elevators  which  not  only  consume  no 
power  in  their  descent,  but  even  reinforce  the 
main  current  with  the  counter-currents  created 
by  their  own  dynamos  revolving  under  stress 
of  their  downward  gravitation.  It  would  be 
difficult  to  make  too  much  of  this  characteris- 
tic, to  which  is  largely  due  the  wonderful 
economy  inherent  in  this  system  of  power  dis- 
tribution, and  which  is  so  prominent  in  the  case 
of  electric  railways  as  to  elicit  the  statement 
from  the  late  Sir  William  Siemens  that  two 
trains  on  the  same  pair  of  rails,  one  ascending 
and  the  other  descending  a  grade,  influenced 
each  other  through  the  common  current  as 
absolutely  as  if  connected  by  an  actual  rope. 

It  is  this  instantaneous  adjustment  through- 
out the  entire  circuit  of  the  supply  of,  to  the 
demand  for,  power  that  precludes  waste  or 
superfluity  of  it. 

It  is,  therefore,  considered  perfectly  prudent 
with  an  ordinary  power  plant  to  contract  to 
deliver  about  double  the  total  capacity  of  the 
generator. 

In  the  problem  under  discussion,  the  quantity 
of  marketable  power  was  limited  to  500  horse 
power,  which  represents  an  annual  rental  of 
$60,000. 

It  thus  -appears  that  every  one  of  the  2,642 
amperes  of  current  flowing  in  the  conductor 
has  a  market  value  of  $22.71  per  annum. 

On  the  other  hand,  the  specified  conductor — 
at  an  assumed  price  of  copper,  say  15  cents  per 
pound — would  cost  $22,248;  the  annual  interest 
on  which,  at  6  per  cent.,  would  create  an  an- 
nual debit  of  $1,335. 

Ohm's  fundamental  law  of  currents  furnishes 
a  useful  point  of  reference  at  this  juncture,  viz. : 

E 

fy  = 

R 

in  which  C  =  current  in  amperes, 
R  =  resistance  in  ohms, 
E  =  electromotive  force,  or  potential, 
in  volts. 

As  the  latter  factor  is  fixed  at  120  volts,  unity 
may  be  substituted  for  it  in  the  formula,  viz. : 

1 

C  —  — 
E 


which  then  signifies  that  the  current  varies  as 
the  reciprocal  of,  or  inversely  as,  the  resistance. 
Colloquially,  it  reads:  having  the  same  electro- 
motive force,  to  double  the  current,  halve  the 
resistance,  and  vice  versa, 

In  conductors  of  similar  material  and  equal 
length,  the  relative  resistances  would  be  in- 
versely proportional  to  their  cross-sections — or 
to  their  weights — and  the  final  deduction  is  that 
currents  of  uniform  potential  moving  in  con- 
ductors of  the  same  material  and  of  equal 
length  vary  as  the  weight  of  the  conductors. 

A  convenient  unit  of  comparison  is  the  an- 
nual market  value  of  the  ampere  which,  as  has 
been  shown,  is  $22.71.  As  the  number  of  salable 
amperes  in  the  case  in  point  is  a  function  of 
the  weight  of  the  conductor,  the  annual  interest 
upon  which  per  pound  is  $.009,  viz.: 
1,335 

148,320 

it  follows  that  it  would  require  the  annual  in- 
terest upon  2,523  pounds  of  copper,  viz.: 

22.71 

=  2,523, 

.009 

to  equal  the  annual  value  of  one  ampere. 

Supposing  the  conductor  to  be  reduced  in 
weight  by  this  amount  and  applying  the  rule 
deduced  for  this  especial  case— of  the  current 
varying  as  the  weight — it  appears  that  such  a 
reduction  would  diminish  the  current  some  45 

amperes,  viz. : 

148,320 
2,523 


148,320    :    145,797     :  :    2,642    :    2,597 

2,642—2,597  =  45, 
whose  annual  value  is  $1,022. 

It  thus  becomes  evident  that  the  diminution 
of  weight  would  entail  vastly  greater  loss  of 
revenue  than  the  annual  saving  achieved 
thereby.  Reducing  the  two  opposing  quanti- 
ties to  a  common  unit  will  give  useful  constants 
for  the  case  under  discussion,  viz. : 

Annual  interest  at  6  per  cent,  on  1  Ib.  copper 
=  $.009. 

Annual  revenue  from  1  Ib.  copper  =  $0. 40. 

Weight  of  copper  per  ampere  =  56  Ibs. 

From  which  it  appears  that  until  the  price  of 
copper  rises  forty -five  times  above  its  present 


THE  ELECTRICAL  TRANSMISSION   OF  POWER. 


47 


figure,  or  the  value  of  the  ampere  falls  the 
same  number  of  times  below  that  assigned  to 
it  in  the  comparison,  or  a  change  occurs  in 
both,  producing  a  similar  mutual  relation,  any 
reduction  of  weight  in  the  conductor — all  other 
factors  remaining  constant — would  be  a  source 
of 'loss  rather  than  of  profit.  Since  it  seems  in- 
contestably  proven  that  for  the  stated  case  and 
specified  conditions  any  diminution  of  the  con- 
ductor would  be  prejudicial,  it  becomes  of  in- 
terest to  know  if  the  weight  might  be  profit- 
ably increased. 

It  will  be  remembered  to  have  been  shown 
above  that  the  given  current  raised  the  tem- 
perature of  the  conductor  4.17°  Fahr.,  which 
increased  its  resistance  .86  of  one  per  cent. 

Since  current  varies  inversely  as  resistance, 
viz., 

100.86  :  100  :  :  2642  :  2619 
2642  —  2619  =  23, 

it  appears  that  this  trifling  increment  reduces 
the  flow  by  23  amperes  whose  annual  value  is 
$522.33.  In  the  given  conductor  and  under  the 
prescribed  conditions,  each  ampere  requires  56 
pounds  of  copper,  and  the  addition  of  1,288 
pounds  (56  x  23  =  1,288),  the  interest  on  whose 
cost  is  but  $11.59,  would  make  good  this  very 
considerable  annual  loss.  Increasing  the  con- 
ductor by  Jhis  amount  of  copper  would  enlarge 
its  cross-section  from  3.25  to  3.30  square  inches 
— a  barely  appreciable  area. 

It  is  evident  that  the  method  employed  is 
only  approximative,  and  may  be  continued  to 
any  desired  degree  of  precision.  There  is  no 
pretence  of  close  accuracy,  and  it  is  even  less 
than  it  might  easily  be,  on  account  of  ignoring 
fractional  quantities  and  the  ordinary  small 
errors  in  the  deduced  factors  made  use  of.  The 
idea  has  been  rather  to  suggest  a  method  of 
dealing  with  such  questions  than  to  furnish 
absolute  results. 

Sir  William  Thomson  has  given  a  formula 
for  computing  the  most  economical  section  of 
conductor,  which  may  in  some  cases  be  used 
with  advantage,  although  it  is  not  adapted  to 
all  cases;  but  here  again  it  must  be  left  to  the 
engineer  to  decide  when  to  use  or  how  to 
modify  the  formula. 

The  resistance  of  any  circuit  may  be  ex- 
pressed by  the  formula, 

I 

E r, 

s 


I  representing  the  length  of  the  conductor,  s  its 
cross-section,  and  r  being  the  specific  resist- 
ance of  the  metal  used — that  is,  the  resistance 
of  a  bar  1  metre  long,  and  having  a  cross-sec- 
tion 1  square  millimetre. 

The  loss  of  energy  through  heat,  expressed  in 
metre-kilogramme-second  units  is 

C*  R       CH  r 
If  j  — 

9.81          s9.8l' 
or  for  unit  length  (1  metre), 

C-r 


.s  9.81 

Now  there  are  31.5  x  ID6  seconds  a  year,  but 
the  current  is  only  used  part  of  this  time — that 
is,  for  31.5  x  10°  X  p  seconds  only  (where  p  rep- 
resents a  fraction  greater  than  zero  and  less 
than  1). 

The  amount  of  energy,  therefore,  lost  in  one 
year  is:  ;u  5  x  io«  x  p  C2  r 

9.81  s 

Let  P  stand  for  the  cost  of  one  horse  power 
per  year;  then  the  cost  of  one  unit  of  work 
(M.  K.  S.  system)  will  be 

P 


31.5  X  10s  x  75' 

and  the  cost  of  A  units — that  is,  of  the  amount 
of  energy  lost  in  a  conductor  1  m.  long  and 
with  s  square  mm.  cross-section — will  be 
P  p  C2r 

9.81  x  75  x  s  ' 

Now,  if  interest  on  investment  capital  be 
taken  at  c  per  cent,  a  year,  and  the  cost  of  one 
cubic  metre  of  the  material  be  v,  then  the  cost 
of  a  conductor  one  metre  in  length  and  s  square 
mm.  cross-section  will  be 

Ll  =  s  v  10-6  c. 
The  total  is: 


L  +  U 


Pp  C*r 


+  v 


9.81  x  75  x  s 
This  will  be  a  minimum  if  L  is  equal  to  L1 


c  s. 


-that  is, 


Pp  C"-r 


9.81  x  75  x  s 
from  which  equation  we  get 


v  10"-"  c  s; 


4 


Pp  C"r 


9.81  X  75  xlO-'x  vc 
or  if  c  =  5, 

s  =  162.56  C 


c\ 


P  p  r  106 


9.81  x  75  x  vc 


J 


P  rp 


v 


CHAPTER  V. 


MODERN  ELECTRIC  RAILWAY  AND  TRAMWAY  IN  EUROPE. 


SOME  experiments  were  tried  in  1867,  at  Ber- 
lin, in  electric  railways,  by  Dr.  Werner  Sie- 
mens, but  the  work  was  abandoned  because  the 
armature  of  the  Siemens  machine  then  used 
became  heated  too  quickly  and  too  greatly  to 
be  of  practical  service.  Under  conditions  of 
more  promise,  the  experiments  were  resumed 
by  Siemens  &  Halske  in  1879,  and  carried  to  a 
successful  issue. 

The  first  step  which  Messrs.  Siemens  took 
towards  a  practical  demonstration  consisted  in 
the  building  of  a  short  line  of  about  500  metres 
length  at  the  Berlin  Exhibition  of  1879.  In  this 
they  employed  their  well-known  type  of  ma- 
chines as  generators  and  motors,  of  which  the 
illustration  shows  one  connected  to  a  Dolgo- 
rouki  rotary  engine,  Fig.  48,  and  a  central  rail 
led  the  current  to  the  machine,  the  outer  rails 
acting  as  a  return  circuit.  Prompted  by  the 
success  with  this  venture,  which  was  the  first 
of  its  kind,  similar  attempts  were  made  in 
Brussels,  Diisseldorf,  and  Frankfort,  for  exhi- 
bition purposes,  with  a  like  result.  The  first 
permanent  undertaking  executed  on  the  Sie- 
mens system,  however,  did  not  take  place  until 
two  years  later,  when,  on  the  12th  of  May,  1881, 
the  line  between  Lichterfelde  and  the  Central 
Cadetten  Anstalt,  near  Berlin,  was  opened  to 
the  public.  This  installation  differed  somewhat 
in  detail  from  the  first  attempts  in  the  manner 
in  which  the  current  was  led;  for  whereas  in 
the  latter  a  third  central  rail  was  used,  the  for- 
mer employed  only  the  two  existing  rails,  one 
as  a  lead  and  the  other  as  a  return  circuit. 

Since  this  road  was  put  in  operation  Messrs. 
Siemens  &  Halske  have  built  numerous  others, 
and  we  need  only  to  mention  those  of  the  Paris 
Exhibition,  at  Vienna,  at  the  Zankeroda  mines 
in  Saxony,  at  Offenbach,  near  Frankfort-on- 
the-Main,  and  the  use  of  the  system  on  the 
Portrush  Railway  in  Ireland,  in  order  to  show 
the  enterprise  of  a  firm  which  American  elec- 
tricians might  well  take  as  an  example. 


The  various  methods  which  the  Siemens  have 
employed  for  conducting  the  current  to  and 
from  the  motor  deserve  some  attention,  as  they 
have  by  no  means  restricted  themselves  to  the 
rails  as  conductors,  but  have  devised  various 
methods  for  the  purpose.  As  stated  above, 
their  first  road  employed  a  central  rail,  while 
the  second  used  the  main  rails  only.  In  order, 
however,  to  avoid  the  danger  of  giving  elec- 
tric shocks  to  persons  and  animals  coming  in 
contact  with  these  unprotected  rails,  and  also 
to  avoid  the  loss  due  to  leakage  between  the 
rails  in  wet  weather,  recourse  has  been  taken 
to  overhead  conductors  which  lead  the  cur- 
rent without  the  objections  just  named. 
The  first  and  most  natural  way  out  of  this 
difficulty  was  to  string  two  wires  overhead 
upon  which  small  trolleys  travelled.  These 
latter  were  connected  to  the  locomotive  by 
wires  which  pulled  them  along,  and  flius  a  con- 
stant circuit  between  motor  and  generator  was 
maintained.  This  method,  though  simple,  was 
found  not  to  work  well  in  practice  on  account 
of  the  vibration  and  the  varying  sag  in  the 
wire,  and  another  was  consequently  devised, 
which  was  first  tried  at  the  Paris  Exhibition  of 
1881,  and  gave  satisfactory  results.  On  this 
occasion  the  overhead  conductors  consisted  of 
brass  tubes,  slit  longitudinally  and  laid  along 
small  stringers  of  wood,  so  that  the  slit  was 
turned  downward.  Within  the  tube  there  was 
placed  a  short  metal  cylinder,  at  the  ends  of 
which  there  projected  two  lugs,  which  passed 
through  the  slit  in  the  tube  and  were  connected 
to  a  small  framework  carrying  a  wheel.  The 
latter  was  pressed  against  the  lower  side  of  the 
tube  by  springs,  and  thus  a  good  contact  was 
obtained  when  the  wire  from  the  locomotive 
was  attached  to  the  device. 

At  the  Zankeroda  mines  still  another  method 
is  employed,  well  suited  to  the  locality.  This 
consists  in  suspending  two  -L  beams  with  their 
flanges  facing  downwards.  The  lower  flanges 


THE  MODERN  ELECTRIC  RAILWAY  AND  TRAMWAY  IN  EUROPE. 


49 


thus  present  a  good  means  for  the  conveyance 
of  a  trolley,  and  the  latter  being  provided  with 
a  brush,  takes  off  the  current,  with  very  little 
loss  of  power.  It  will  be  seen  that  for  mines 
this  disposition  of  the  conductors  is  a  very 
happy  one.  The  rough  usage  to  which  the 
rails  are  subjected,  together  with  the  frequent 
presence  of  water,  makes  the  employment  of 
the  former  as  conductors  impracticable;  but  the 
_L  rails  suspended  close  to  the  roof,  and  attached 
to  hard  rubber  insulators,  leave  little  to  be  de- 
sired in  the  matter  of  efficiency.  The  motor  at 


application  of  electricity  as  the  chief  motive 
power  for  propelling  the  tram-car;  and  5th. 
The  use  of  water-power  as  the  actual  source 
from  which  the  motive  power  is  derived.  The 
line  is  a  continuous  series  of  long  inclines. 
Gradients  one  in  forty-five  and  one  in  forty  are 
frequent  for  upward  of  a  mile  in  length,  while 
steeper  gradients  of  one  in  thirty  exist  for 
shorter  distances,  the  worst  gradient  being  one 
in  twenty-five,  the  total  rise  from  the  depot  at 
Portrush  to  the  summit  being  203  feet.  The 
system  finally  adopted  of  utilizing  electricity 


FIG.  48. — SIEMENS'  DYNAMO  WITH  DOLGOROUKI  ENGINE. 


these  mines  weighs  about  li  ton  and  is  capable 
of  hauling  a  load  of  eight  tons  at  the  rate  of 
seven  or  eight  miles  an  hour. 

The  main  features  of  the  Portrush  road  were 
described  by  Dr.  Anthony  Traill,  LL.  D.,  chair- 
man of  the  Portrush  Electric  Railway,  at  the 
Montreal  meeting  of  the  British  Association  for 
the  Advancement  of  Science,  in  1884.  This  line, 
he  said,  was  specially  constructed  with  a  view  to 
the  application  of  electricity  as  a  motive  power. 
The  chief  distinctive  features  by  which  it  differs 
from  tramways,  as  usually  constructed,  are:  1st. 
The  gauge,  which  is  three  feet;  3d.  The  posi- 
tion of  the  tramway  in  respect  to  the  side  of  the 
road,  viz..  it  being  placed  alongside  of  the  road, 
and  not  in  a  central  position,  and  being  raised 
slightly  above  the  surface  of  the  road;  3d.  The 
form  of  the  rail,  a  flange  being  substituted  for 
a  grooved  rail;  4th.  The  motive  power,  the 
7 


as  the  motive  power  differs  from  the  system 
used  on  the  Lichterfelde,  the  Charlottenburg 
and  the  Paris  electric  tramways,  where  over- 
head electric  conductors  or  storage  batteries 
were  used.  The  track  being  laid  along  the  side 
of  the  road,  a  third  rail  or  rigid  electric  con- 
ductor is  placed  along  the  toe  of  the  fence  or 
ball,  consisting  of  from  twenty  to  thirty  foot 
lengths  of  T  irons,  weighing  nineteen  pounds 
to  the  yard,  supported  on  short  wooden  posts 
with  insulating  caps  of  "insulite,"  the  top  sur- 
face of  the  conducting  rail  being  three  inches 
wide  and  eighteen  inches  above  the  level  of  the 
tramway  rails.  The  ordinary  track  rails  con- 
stitute the  "return."  completing  the  circuit. 
The  electricity  is  now  generated  by  water 
power  on  the  River  Bush,  situated  at  a  distance 
of  1,GOO  yards  from  the  nearest  point  of  the 
tramway,  and  five  and  a  half  miles  from  Port- 


/- 


50 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


rush,  Fig.  49.  A  fall  of  twenty-six  feet  head  of 
water  is  used  to  drive  two  of  Alcott's  turbines, 
each  capable  of  working  up  to  fifty-two  horse 
power.  These  drive  on  a  single  shaft,  which 
communicates  by  belting  with  a  generating 
Siemens  dynamo,  giving  a  maximum  current 
of  100  amperes  with  250  volts  E.  M.  F.  Each 
electric  car  is  fitted  with  a  starting  handle  at 
each  end,  and  with  powerful  brakes,  and  is 
capable  of  drawing  a  second  car  behind  it,  with 
a  total  complement  of  44  passengers  comfort- 
ably seated.  The  daily  running  of  the  elec- 
tric cars  commenced  on  November  5,  1883, 
from  which  date  till  July,  1884,  upward  of 
13,000  electrical  train  miles  had  been  run.  The 
working  expenses  of  the  electrical  train  mile 
are  five  cents  a  mile  as  compared  with  eleven  and 
twelve  cents  per  steam  engine  train  mile,  and 
the  average  cost  of  twenty  cents  to  twenty- 
four  cents  per  mile,  when  horse  power  is  used. 
The  line  continues  down  to  the  present  time  in 
most  successful  operation.  An  extension  of  six 
miles  is  in  contemplation,  and  a  12  per  cent. 
dividend  is  paid.  Speaking  before  the  Invent- 
ors' Institute  in  1885,  Mr.  Traill,  the  engineer  of 
the  road,  stated  that  30,000  train  miles  had  then 
been  run,  and  that  100,000  passengers  had  been 
carried.  He  also  said  that  after  repeated  trials 
the  management  had  found  an  efficient  method 
of  making  contact  between  train  and  conductor. 
This  consists  in  the  use  of  a  steel  spring  in  the 
shape  of  a  carriage  spring;  two  of  these,  con- 
cave, are  fastened  at  the  top  and  rub  along 
the  bottom.  The  cost  and  the  wear  are  nomi- 
nal. The  total  resistance  of  the  line  from  the 
generator  and  back  is  1.9  ohms.  Where  the 
rails  are  crossed  by  roads,  an  insulated  cable  is 
laid  under  ground  and  it  connects  the  two  ends 
of  the  severed  rails,  so  that  the  latter,  though 
elevated  along  the  line,  do  not  prevent  the 
crossing  of  vehicles.  As  there  are  two  sets  of 
brushes  attached  to  the  motor,  one  in  front  and 
the  other  in  the  rear,  it  follows  that  at  short 
crossings  the  front  brush  makes  contact  before 
the  rear  one  has  left  the  rail,  and  thus  an  unin- 
terrupted current  is  maintained.  Where  the 
crossing  is  greater  than  the  length  of  the  car, 
the  momentum  of  the  latter  carries  it  over  to 
the  opposite  end,  and  in  this  manner  makes 
connection  again. 

The  Siemens  line  at  Lichterfelde,  a  suburb  at 
Berlin,  has  been  in  operation  since  May,  1881. 
The  rails  rest  on  insulated  sleepers.  One  rail  is 


positive  and  the  other  negative,  or  return.  The 
gauge  is  three  feet  three  inches.  Each  car  is 
driven  by  its  own  motor,  and  has  a  carrying 
capacity  of  26  passengers.  The  movement  of 
the  motor  armature  is  transmitted  to  the  car 
wheels  by  means  of  a  belt  working  on  cylinders 
outside  the  wheels.  The  cars  are  provided  with 
brakes,  which  may  be  put  on  at  either  end,  so 
that  they  will  run  in  either  direction  without 
being  turned  around  on  the  track.  Yet  another 
Siemens  road  was  put  in  operation  between 
Modling  and  Bruhl,  near  Vienna,  in  1884,  for  a 
distance  of  over  two  miles.  This  line  has  since 
been  in  course  of  extension  to  Hinterbriihl, 
making  it  about  a  third  longer. 

The  cities  of  Frankfort  and  Offenbach  are  con- 
nected by  a  Siemens  electric  railway,  6,665  me- 
tres (about  4  1-8  miles)  long,  of  39  inches  gauge. 
It  leads  from  the  old  "  Romerbriicke  "  Frank- 
fort, through  Sachsenhausen,  Oberrad,  and 
through  the  entire  town  of  Offenbach.  The 
trains  run  over  the  entire  route  in  about  25 
minutes.  Two  steam  engines,  of  125  horse 
power  each,  drive  four  dynamo-electric  ma- 
chines and  the  current  is  conducted  through 
suitable  cables  and  conductors  over  the  entire 
line.  A  switch  is  provided,  regulating,  govern- 
ing, and  directing  the  currents,  as  may  be 
necessary.  The  conductors  consist  of  tubes 
slotted  along  their  entire  length  at  the  bottom, 
and  insulated  on  poles  in  about  the  same 
manner  as  telegraph  wires  are  arranged.  In 
these  tubes  a  small  cylinder  slides  or  runs, 
from  which  a  conductor  extends  down  to  the 
car  and  to  the  dynamo  in  the  same  in  the  usual 
manner. 

We  have  entered  into  this  detailed  descrip- 
tion of  the  methods  employed  in  the  Siemens 
system,  because  the  points  involved  are  of  great 
importance,  and  may  often  determine  the  prac- 
tical success  of  similar  undertakings.  As  re- 
gards a  choice  of  conductors  for  electric  rail- 
ways, it  is  obvious  that  no  definite  rule  can  be 
laid  down,  as  the  method  employed  must  be 
governed  entirely  by  the  exigencies  of  the  case. 
It  is  thus  seen  that  at  Lichterfelde,  which  is 
but  sparsely  populated  and  has  but  little  traffic, 
the  rails  alone  have  been  used  as  conductors. 
In  Paris  the  case  was  entirely  changed,  for 
there  the  rails  lay  flush  with  the  street,  the 
city  authorities  not  permitting  a  raised  rail  to 
interfere  with  the  continuity  of  the  pavement. 
This  prevented  good  insulation,  and,  in  ad- 


FIG.  49.-THE  WATER  POWER  OF  THE  PORTRUSH  RAILRO, 


\D. 


52 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


dition,  the  sunken  rail  permitted  the  accumu- 
lation of  dirt  and  other  matter  which  would 
have  prevented  the  wheels  from  making  good 
contact.  All  this  being  foreseen,  it  became 
necessary  to  provide  overhead  conductors,  tak- 
ing the  form  described  above.  At  the  Zanker- 


FIG.  50. — TUNNEL  FOR  VIENNA  ELECTRIC  RAILWAY. — 
LONGITUDINAL  SECTION. 

oda  mines  the  form  adopted  seems  eminently 
practical,  and  will  no  doubt  be  copied  in  future 
installations.  The  exemplifications  might  be 
continued,  but  those  enumerated  will  suffice  to 
show  what  has  been  done  in  that  direction,  and 
to  point  the  way  to  a  selection  of  the  best 
method  to  be  applied  to  a  given  case. 


FIG.  51. — TUNNEL  FOR  VIENNA  ELECTRIC   RAILWAY. — 
TRANSVERSE  SECTION. 

We  now  come  to  the  consideration  of  the 
proposed  Vienna  system  of  electric  railways 
which  has  been  elaborated  by  Siemens  &  Halske, 
and  which,  if  carried  out,  will  undoubtedly 
place  that  city  in  the  front  rank  as  regards 
transportation  facilities  within  city  limits. 


The  projectors  start  out  with  the  proposition 
that  no  such  railway  can  be  run  on  the  surface 
of  the  street,  for  the  reason  that  contact  with 
the  rails  would  be  unavoidable,  especially  at 
car  crossings,  and  principally  on  account  of  the 
limited  speed  which  surface  railways  are 
obliged  to  run  at.  Where  quick  transit  is  desir- 
able, therefore,  the  solution  must  be  sought  either 
in  an  underground  or  an  elevated  system,  or  h< 


UOtcrrauL  woRm 

i:  \ 
FIG.  52. — KLEVATED  STRUCTURE  FOR  VIENNA  RAILWAY. 

a  combination  of  both,  depending  upon  the 
nature  of  the  surface.  The  last  named  plan  is 
the  one  proposed  for  Vienna,  where  the  rise 
and  fall  of  the  ground  would  present  too  heavy 
grades  for  either  one  of  the  first  two  systems 
mentioned.  It  is  therefore  proposed  to  build  a 
road  in  which  tunnels  shall  alternate  with  ele- 
vated structures,  and  the  manner  of  building 
both  of  these  is  shown,  as  they  give  a  good  idea 
of  the  requirements  of  the  case;  Figs.  50,  51, 
and  52. 


THE  MODERN  ELECTRIC  RAILWAY  AND  TRAMWAY  IN  EUROPE. 


53 


As  regards  the  construction  of  the  tunnel,  of 
which  we  give  two  views,  it  will  be  seen  to 
have  a  flat  roof  instead  of  an  arched  one.  This 
is  necessary,  because  the  latter  construction 
would  require  a  greater  height  of  tunnel,  and 
in  addition  an  increased  width.  One  object  in 
making  the  tunnel  as  low  as  possible  is  to  mini- 
mize the  grades  in  passing  from  tunnel  to  via- 
duct, and  by  making  the  tunnel  as  narrow  as 
possible,  plenty  of  room,  even  in  the  narrowest 


Respecting  the  viaduct  or  elevated  portion 
of  the  road,  an  essential  condition  requires  it 
to  be  as  simple  as  possible.  It  must  be  open  so 
as  not  to  obstruct  the  light,  and  this  requires 
the  parts  to  be  small  and  simple.  Hence  the 
illustration  shows  both  rails  supported  by  only 
one  main  girder  bracing  between  them.  It  is 
asserted  also  that  this  method  of  construction 
will  diminish  the  noise  of  passing  trains — a 
boon  that  only  the  dwellers  along  the  lines  of 


FIG.  53. — THE  BRIGHTON,  ENGLAND,  ELECTRIC  RAILWAY. 


streets,  remains  on  both  sides,  for  the  placing 
of  sewer  and  other  pipes,  without  interfering 
with  the  foundations  of  houses.  Ventilation 
of  the  tunnel  will  be  effected  by  means  of  per- 
forated plates  inserted  in  the  roof  and  arranged 
so  as  to  catch  any  matter  that  might  fall 
through  the  holes.  They  would  so  act  that 
when  a  train  approached  one  of  them  it  would 
force  out  the  foul  air  through  the  openings, 
and  as  it  receded  it  would  draw  in  a  supply 
of  fresh  air;  plates  thus  placed  at  proper  inter- 
vals would  maintain  good  ventilation.  It  goes 
without  saying  that  the  cars  are  to  be  lighted 
by  electricity. 


the  rattling  and  vibrating  New  York  elevated 
roads  can  appreciate  in  its  full  extent.  The 
course  that  these  lines  will  take  in  Vienna  de- 
mands attention.  Although  it  is  not  proposed 
to  build  the  entire  road  at  once,  the  plan  has 
been  so  worked  out  that,  when  complete,  the 
system  will  present  a  network  giving  access 
to  all  parts  of  the  city,  from  any  starting  point, 
in  the  shortest  time.  We  can  best  explain  the 
course  of  the  road  by  asking  our  readers  to 
imagine  a  circle  drawn:  around  this  inner 
circle  there  are  drawn  others  in  such  a  man- 
ner that  each  one  shall  touch  its  neighbor  and 
also  form  part  of  the  circumference  of  the 


FIG.  51. — THE  PARIS  ELECTRIC  STREET  RAILWAY  OK  1881. 


FIG.  55. — THE  PARIS  ELECTRIC  STREET  RAILWAY  OF  1881. 


THE  MODERN  ELECTRIC  RAILWAY  AND  TRAMWAY  IN  EUROPE. 


55 


inner  circle.  It  will  thus  be  seen  that  any  part 
of  the  city  can  be  reached,  no  matter  in  what 
direction,  in  the  shortest  time  consistent  with 
such  a  comprehensive  plan.  It  will  of  course 
be  understood  that  the  lines  proposed  do  not 
take  the  shape  of  true  circles. 

An  English  railway  that  has  been  a  notable 
success,  though  on  a  small  scale,  is  that  oper- 
ated during  the  past  two  years  at  Brighton,  the 
well-known  watering  place,  by  Mr.  Magnus 
Volk.  The  line,  Fig.  53,  is  rather  under  a 
mile  in  length,  and  includes  some  heavy  gradi- 
ents on  sharp  curves,  the  gauge  being  2.9.  The 
speed  is  limited  to  eight  miles  an  hour,  but  a 
speed  of  over  twenty-five  miles  has  been  ob- 
tained. The  current  is  transmitted  along  the 
rails,  which  are  fastened  to  wooden  sleepers 
resting  on  the  shingle,  no  special  insulation 
being  used.  Each  car  seats  thirty  passengers, 
and  the  motor  can  draw  another  if  necessary. 

The  plant  comprises  two  cars  fitted  with 
motors;  one  eight  horse  power  gas  engine,  one 
twelve  horse  power  gas  engine,  one  Siemens 
D2  series  dynamo,  one  Siemens  D2  compound 
dynamo. 

The  working  expenses  for  one  year  are  given 
as  follows  (average  for  two  years):  Electrical 
machinery  —  new  commutators  and  brushes, 
$48.12;  gas  engines — refacing  slides,  etc.,  $31.17; 
oil  and  waste  (that  used  for  axles  included), 
$48.30;  gas  (including  that  used  to  light  premi- 
ses, price  78  cents  per  1,000  cubic  feet),  $547.93; 
attendant,  52  weeks,  at  $4.32,  $224.04;  total, 
$900.16.  The  gross  earnings  per  car  mile  are 
38  J-  cents ;  the  gross  expenses  (all  renewals 
being  paid  out  of  revenue),  22J  cents;  car  mile- 
age per  annum,  23,475;  cost  of  haulage  per  car 
mile,  3.84  cents,  barely  4  cents;  this  includes 
the  engine  attendant. 

Only  one  car  is  running,  except  on  bank  holi- 
days, etc.,  on  which  occasion  nearly  all  the 
power  of  the  12  horse  engine  is  used.  The  re- 
pairs to  the  electrical  machinery  only  amount 
to  5  per  cent,  per  annum,  and  to  the  gas  engine 
only  about  2|  per  cent.  The  only  repairs  to  the 
electrical  machinery  of  the  two  cars — the  work 
having  been  nearly  equally  divided,  each  car 
having  run  about  25,000  miles— have  been  one 
new  commutator  and  one  spindle  bush  relined 
with  soft  metal;  that,  therefore,  represents  the 
wear  and  tear  for  nearly  50,000  miles  running. 
The  extra  cost  of  running  two  cars  is  very 
slight,  only  about  two-thirds  more  gas  being 


required,  and  the  other  expenses  being  scarcely 
affected. 

Figs.  54  and  55  illustrate  the  electric  car  used 
during  the  Paris  Electrical  Exposition  of  1881, 
and  referred  to  above.  This  car  carried  84,- 
000  persons.  The  motor  was  placed  under  the 
car  body.  The  second  view  shows  the  car  turn- 
ing the  sharp  curve  from  the  Champs  Elysees 
to  the  Palais  de  1'Industrie,  where  the  exposi- 
tion was  held.  The  first  view  shows  the  car 
from  the  other  side,  so  as  to  make  plain  the 
method  of  taking  the  current  from  the  conduct- 
ors placed  on  poles  and  parallel  with  the  line 
of  track. 

The  Siemens  road  that  was  in  operation  at  the 
Vienna  Electrical  Exposition  in  1883,  is  illus- 
trated in  Fig.  56.  The  track  was  1528  metres  in 
length,  A  Siemens  motor  was  placed  under  the 
floor  of  each  of  the  two  end  cars,  and  the  current 
was  furnished  by  two  Siemens  dynamos  coupled, 
so  that  the  current  from  each  armature  excited 
the  other's  field  magnets.  One  rail  was  con- 
nected with  the  positive  binding  post  common 
to  both  machines,  and  the  other  rail  with  the 
negative  post  alike  belonging  to  each.  An 
electromotive  force  of  150  volts  was  main- 
tained. 

The  road  most  worthy  of  notice  in  England 
after  those  at  Portrush  and  Brighton  is  that  of 
Mr.  Holroyd  Smith,  at  Blackpool.  On  the 
Blackpool  tramway  every  means  has  been 
taken  to  reduce  the  objections  of  electric  lines 
in  cities  to  a  minimum,  as  will  be  seen  by  our 
illustration,  Fig.  59,  which  represents  a  part 
section  of  the  road-way  in  perspective.  The 
entire  electrical  part  of  the  road  is  below  the 
surface  of  the  street,  and  the  rails  are  not  used 
as  a  conductor.  The  latter  consists  of  two  cop- 
per tubes,  C,  of  elliptical  shape,  and  having  a 
wide  slot  for  facility  of  attachment  to  iron  studs, 
S,  which  are  supported  in  porcelain  insulators,  /. 
The  latter  are  themselves  attached  to  blocks  of 
creosoted  wood  in  the  sides  of  the  channel. 
The  tubes  are  fixed  to  the  studs  by  the  simple 
device  of  a  wooden  pin  wedge,  W,  and  they  are 
coupled  to  each  other  by  two  metallic  wedges, 
as  shown  in  our  illustration,  Fig.  58. 

The  car  which  is  employed  is  shown  in  plan  and 
in  longitudinal  section,  in  Figs.  57  and  00,  which 
are  so  clear  that  no  extended  description  ap- 
pears to  be  necessary. 

At  each  end  of  the  car  there  is  a  switch-box 
with  resistance  coils  placed  under  the  plat- 


56 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


THE  MODERN  ELECTRIC  RAILWAY  AND  TRAMWAY  IN  EUROPE. 


forms,  by  which  means  the  strength  of  the  cur- 
rent and  speed  of  the  car  can  be  regulated.  To 
reverse  the  direction  in  which  the  car  is  travel- 
ling, the  direction  of  the  current  through  the 
armature  is  reversed,  the  field  magnets,  which 
are  shunt-wound,  remaining  always  magnetized 
in  the  same  sense.  With  this  arrangement  there 
is  no  need  to  alter  the  position  of  the  brushes, 
which  in  this  case  consist  of  two  parallel  sets 
of  plates  placed  tangentially  to  the  commu- 
tator, and  pressed  on  it  by  spiral  springs. 
There  is  only  one  handle  to  the  two  switch- 
boxes,  and  that  being  in  possession  of  the 
driver,  the  possibility  of  accidents  caused  by 
interference  of  others  with  the  electrical  con- 
nections is  precluded.  The  current  is  generated 
by  four-pole  El  well-Parker  dynamos,  Fig.  61, 
and  the  motors  are  also  manufactured  by  that 
firm.  The  line  is  in  continuous  and  highly 
successful  operation.  It  is  about  two  miles  in 
length. 

The  dynamos  are  three  in  number,  two  of 
extra  large  size  for  generating  the  electricity 
for  driving  the  cars,  and  the  third  a  much 
smaller  one,  for  exciting  the  "generators." 
These  machines  were  manufactured  specially 
for  this  work  by  Elwell-Parker,  Limited,  of 
Wolverhampton.  The  "  exciter,"  Fig.  02,  is  of 
their  usual  type.  The  length,  including  pulley, 
is  3ft.  3  in. ;  width,  2ft.;  and  height,  2ft;  its 
total  weight  is  about  10  cwt.  The  diameter  of 
the  armature  is  10  in.,  with  a  length  of  13  in. 
The  resistance  of  the  field  magnets  is  60  ohms, 
and  the  electromotive  force  is  150  volts,  with  a 
current  of  10  amperes.  The  brushes  and  com- 
mutator are  of  the  usual  form.  The  generators, 
Fig.  01,  are  among  the  largest  of  this  form  of 
dynamo  yet  constructed,  and,  as  may  be  seen, 
differ  materially  from  the  Elwell-Parker  type; 
each  dynamo  consists  of  two  field  magnets, 
with  a  commutator  carrying  four  sets  of 
brushes  in  pairs.  These  brushes  are  fitted  with 
springs,  which  are  easily  adjustable,  so  that 
they  can  be  kept  just  clear  of  the  commutator 
or  instantly  dropped  into  contact.  These  ma- 
chines are  7  ft.  3  in.  long  over  all,  5  ft.  8  in.  wide, 
and  2ft.  high,  weighing  altogether  about  four 
tons;  they  are  provided  with  slides  and  adjust- 
ing screws,  are  run  at  a  speed  of  about  050 
revolutions,  and  produce  an  electromotive  force 
of  from  200  to  300  volts  (according  to  speed), 
and  a  current  of  about  180  amperes;  the  resist- 
ance of  the  field  magnets  is  about  30  ohms,  and 


that  of  the  armature  .004  ohm;  the  armature  is 
3  ft.  long  by  16  in.  diameter,  and  from  the  illus- 
tration it  can  be  seen  that  it  is  well  ventilated. 
The  machine  is  massive  in  construction,  and 
well  finished,  and  it  is  said  to  run  with  the 
greatest  freedom  from  heating  in  all  parts,  a 
very  desirable  feature.  The  dynamo  or  motor  in 
the  cars  is  run  at  a  speed  of  800  revolutions  per 
minute,  with  an  electromotive  force  of  200  to 
250  volts,  and  a  current  of  about  20  amperes; 
the  resistance  of  the  field  circuit  is  14  ohms, 
and  that  of  the  armature  .074  ohm.  There  is 
one  point  of  interest  to  which  it  is  necessary 
to  call  attention,  and  that  is  the  position  of  the 
brushes  with  regard  to  the  commutator.  The 
cars, which  are  13  ft.  0  in.  long  by  0  ft.  6  in.  wide, 
are  arranged  so  that  their  position  remains  un- 
changed on  the  line,  and  consequently  it  be- 
comes necessary  to  reverse  the  "motor"  to 
drive  the  car  either  forward  or  backward.  If 
brushes  were  fixed  in  the  ordinary  way  they 
would  be  right  for  proceeding  in  the  one  direc- 
tion, but  reverse  motion  would  at  once  double 
back  the  copper  wires  of  the  brush.  The 
brushes  are  therefore  fixed  as  near  as  possible 
opposite  the  centre  of  the  commutator,  and-  are 
therefore  in  the  same  plane  and  exactly  at 
right  angles  to  a  line  drawn  perpendicularly 
through  the  commutator.  Their  ends  press  di- 
rectly against  the  bars  of  the  commutator,  and 
they  are  fixed  relatively  to  each  other,  and  so 
balanced  that  any  alteration  in  the  position  of 
the  one  produces  a  corresponding  alteration  in 
the  other,  §0  that  the  brushes  are  kept  exactly 
opposite  each  other.  The  switch  arrangement 
of  the  cars  consists  of  two  portions,  one  a 
switch  for  reversing  the  direction  of  the  cur- 
rent, and  the  other  for  starting  the  car.  The 
former  controls  the  direction  of  the  motion,  the 
latter  its  starting  and  stopping,  and  also  its  rate 
of  progress. 

These  switches  are  contained  in  wooden 
pedestals  placed  under  the  steps  leading  to  the 
roof,  one  at  each  end.  The  starting  switch 
consists  of  a  projecting  handle,  which  is  moved 
forwards  or  backwards;  this  handle  is  screwed 
on  to  the  end  of  the  inside  switch,  which, 
moving  over  certain  brass  contact  pieces,  brings 
into  the  circuit  between  the  charged  conductor 
and  the  motor  certain  resistances  which  have 
the  effect  of  diminishing  the  speed  of  the  arma- 
ture of  the  motor.  It  will  be  seen,  therefore, 
that  a  slight  alteration  of  the  handle,  altering 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


FIG.  57. — PLAN  OF  CAK. 


FIG.  58. — DETAILS  OK  CONDUCTOR   IN  CONDUIT. 


Fio.  59. — SECTION  OF  KOADNVAY. 


FIG.  (JO. — BLACKPOOL,  ENGLAND,  ELECTKIC  STREET  CAR. 


THE  MODERN  ELECTRIC  RAILWAY  AND  TRAMWAY  IN  EUROPE. 


the  resistance  in  circuit,  produces  the  required 
effect  in  increasing  or  decreasing  the  speed  of 
the  motor.  These  resistances  are  made  of 
carbon  rods  (similar  to  those  used  in  an  electric 
arc  lamp)  firmly  attached  to  brass  connecting- 
pieces. 

The  Besspool  electric  tramway  was  inspected 
and  passed  without  alteration  by  the  English 
government  authorities  in  1885,  and  has  lately 
been  accepted  from  the  contractors  as  satisfac- 
tory. It  has  been  constructed  to  form  a  link 
between  the  mills  and  granite  quarries  of  the 
Bessbrook  Spinning  Company  and  the  railway 
at  Newry,  the  distance  between  the  two  places 


The  flangeless  wheels  run  upon  these  outside 
rails.  The  maximum  gross  load  of  a  train  is 
twenty-six  tons,  consisting  of  six  wagons,  which 
carry  about  two  tons  each,  and  the  electric 
locomotive,  weighing  eight  tons,  which  also 
forms  the  passenger  carriage,  and  is  capable 
of  accommodating  thirty-four  passengers.  This 
load  can  be  drawn  up  inclines  averaging  one 
in  eighty-five  at  a  speed  of  seven  miles  an 
hour,  and  up  the  stiffest  incline  of  one  in  fifty 
at  a  speed  of  six  miles  an  hour.  The  train 
can  be  started  at  any  point  of  the  line  without 
difficulty.  The  motive  power  is  electricity  fur- 
nished by  dynamos  situated  about  two  miles 


FlG.  61. — (iF.XKHATOR  AT  BLACKPOOL. 


being  three  miles,  and  the  annual  traffic,  which 
has  hitherto  been  carried  in  carts,  being  about 
-.'s.ooo  tons.  The  tramway  differs  from  others 
in  that  the  vehicles  are  equally  well  adapted 
to  run  on  the  rails  and  the  ordinary  roads,  this 
facility  being  required  by  the  difficulty  which 
was  found  in  connecting  the  line  to  the  railway 
at  one  end,  and  to  every  department  of  the 
works  at  the  other.  They  are  carried  on  four 
wheels  2£  inches  wide  and  without  flanges;  the 
first  pair  are  on  a  bogie,  which  can  be  fixed  to 
form  a  rigid  wheel  base,  or  have  shafts  fitted  to 
it,  and  allowed  to  swivel  after  the  manner  of 
the  leading  axle  of  a  coach.  These  wagons 
carry  two  tons  each,  and  can  be  drawn  by  a 
horse  up  moderate  grades.  On  the  outside  of  the 
ordinary  tramway  rail,  second  rails  have  been 
laid,  to  which  the  ordinary  rails  act  as  guards. 


from  Newry,  at  Millvale,  and  driven  by  a  tur- 
bine, constructed  capable  of  developing  sixty- 
five  horse  power.  The  conductor  consists  of 
an  inverted  steel  channel  carried  on  insulators, 
and  fixed  midway  between  the  ordinary  rails. 
Both  the  generators  and  motors  are  of  the 
Edison-Hopkinson  type,  constructed  by  Messrs. 
Mather  &  Platt,  and  are  capable  of  developing 
twenty-five  horse  power.  The  locomotive  is 
geared  to  run  at  a  maximum  speed  of  fifteen 
miles  per  hour,  and  this  speed  is  easily  attained 
when  there  are  no  trucks  attached.  The  cars 
are  35  feet  long  over  all,  and  are  carried  on 
bogies  at  each  end,  so  that  they  pass  readily 
around  curves  of  55  feet  radius. 

M.  Lartigue,  the  well-known  French  engineer, 
has  applied  electricity  to  the  traction  of  the 
panniers  or  cars  of  his  single-rail  tramway. 


60 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


This  tramway  is  employed  in  Algeria  for  trans- 
porting esparto  grass  from  the  interior  by  the 
traction  of  camels.  It  was  an  easy  step  from 
animal  to  electric  traction,  and  M.  Lartigue  has 
successfully  taken  it.  At  a  recent  Agricultural 
Exhibition  in  the  Palais  de  PIndustrie  of  Paris, 
a  line  was  shown  on  which  five  iron  panniers, 
or  double  cars  in  the  form  of  seats,  were  drawn 
by  an  electric  locomotive  at  the  rate  of  seven 


was  carried  by  a  platform  car  or  pannier,  and 
geared  with  a  grooved  driving-wheel  thirty 
centimetres  in  diameter,  which  ran  upon  the 
rail.  A  rheostat  to  graduate  the  speed,  switches 
to  stop,  start,  and  reverse  the  motor,  and  a  seat 
for  the  conductor,  were  also  carried  by  the  loco- 
motive, and  ran  on  small  grooved  wheels.  The 
current  was  brought  to  the  dynamo  by  two 
insulated  conductors,  one  connected  to  the  rail, 


FIG.  62. — EXCITER,  BLACKPOOL  ROAD. 


miles  an  hour.  The  total  weight  of  the  five 
cars  and  the  electric  locomotive  was  about  a 
ton,  and  the  maximum  power  required  was 
three  horse  power.  The  dynamo  of  the  loco- 
motive was  a  Siemens  Dt,  and  the  generator, 
which  stood  about  100  yards  from  the  line,  was 
a  Siemens  Z>s  dynamo  capable  of  developing 
from  five  to  six  electric  horse  power.  It  was 
driven  by  a  Herman-Lachapelle  steam  engine. 
The  total  length  of  the  line  was  123  metres. 
It  was  built  of  forty -one  rails,  each  three  metres 
long,  and  comprised  curves  of  seven  and  one- 
half  metres  radius.  The  locomotive  dynamo 


the  other  to  the  dynamo  through  small  con- 
tact rollers  in  connection  with  the  commutator. 
One  switch  was  employed  to  start  or  stop  the 
train  by  making  or  breaking  the  circuit;  the 
other  to  reverse  its  motion  by  reversing  the 
current.  The  rheostat,  by  interpolating  resist- 
ance into  the  circuit,  allowed  the  strength  of 
the  current  to  be  varied  and  the  speed  of  the 
train  to  be  increased  or  diminished  as  the  case 
may  be.  The  work  was  carried  out  by  Messrs. 
Siemens,  and  under  the  direction  of  M.  G. 
Boistel.  The  economy  of  the  working  is  of 
course  largely  dependent  on  local  circumstances. 


CHAPTKR  VI. 


THE  MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE 

IN  AMERICA. 


THE  narrative  of  invention  and  experiment 
given  in  Chap.  III.  has  already  detailed  the  nu- 
merous efforts  made  in  America  to  work  out  the 
solution  of  the  many  difficult  problems  en- 
countered in  electric  railroading.  It  has  also 
shown  beyond  question  that  down  to  the  time 
of  the  discovery  of  the  reversibility  of  the  dyn- 
amo, such  work,  no  matter  how  ingeniously 
and  persistently  carried  out,  was  doomed  to 
failure.  But  with  the  advancing  efficiency  of 
the  dynamo  as  a  generator  or  as  a  consumer  of 
current,  and  with  the  success  of  the  Paris  Elec- 
trical Exposition  in  1881,  came  a  revival  of  in- 
terest in  the  subject,  and  such  a  display  of 
energy  and  ability  in  this  field  in  America  as  to 
have  brought  the  idea  to  triumphant  realiza- 
tion within  the  brief  period  of  five  years. 

To  Mr.  Stephen  D.  Field,  a  member  of  the 
distinguished  Field  family,  the  United  States 
Patent  Office  has  awarded  priority  of  invention 
in  electric  railways  in  America.  The  papers  of 
Mr.  Field  were  filed  in  Washington  on  March 
10,  1880  (a  caveat  was  filed  May  21,  1879);  those 
of  Dr.  Werner  Siemens  on  May  12,  1880,  and 
those  of  Mr.  Tho'mas  Alva  Edison,  on  June  5, 
1880.  These  inventors  were  placed  in  inter- 
ference, and  it  was  not  until  last  year  that  a 
declaration  was  made  in  favor  of  Mr.  Field,  on 
the  combination  of  an  electric  motor  operated 
by  means  of  a  current  from  a  stationary  source 
of  electricity  conducted  through  the  rails.  In 
view  of  what  had  been  accomplished  before 
Mr.  Field  secured  his  patent,  it  is  altogether 
unlikely  that  he  will  be  left  in  quiet  enjoyment 
of  the  rights  thus  conferred.  In  fact,  it  is  one 
of  the  peculiarities  of  electrical  invention  to 
develop  colossal  litigations,  and  we  do  not  be- 
lieve that  electric  railways  will  be  any  excep- 
tion to  the  rule.  Probably  the  electric  motor 
companies  now  springing  into  vigorous  exist- 
ence will  depend  for  future  life  not  so  much 
upon  such  fundamental  patents  as  upon  the 


control  of  important  details  of  construction  and 
application. 

A  very  interesting  and  authoritative  account 
of  the  work  of  Mr.  Field  in  this  line  appeared 
in  the  New  York  Mail  and  Express  of  August 
2,  1884,  and  is  here  quoted  in  part: 

"In  his  boyhood  he  showed  a  taste  for  me- 
chanics and  for  electrical  experimenting.  He 
became  a  telegraph  operator  before  he  was  six- 
teen, up  among  the  hills  of  Berkshire  county, 
where,  after  two  removals  across  a  continent, 
he  at  last  proved  the  electric  railway  a  success. 
In  his  17th  year  the  boy  went  with  his  family 
to  San  Francisco.  He  was  first  employed  in 
California  as  an  operator  for  the  California 
State  Telegraph  Company.  In  18G5  he  assisted 
in  the  construction  of  the  Russo-American 
Telegraph  Line,  under  the  direction  of  Mr. 
Frank  L.  Pope,  whom  he  had  known  as  a  boy 
in  Massachusetts,  and  who  afterward,  as  a 
patent  solicitor,  entered  his  application  for  a 
patent  on  the  electric  railway.  It  was  in  this 
year  that  he  first  learned  of  the  successful 
solution  of  the  problem  of  producing  electric 
currents  by  mechanical  means  in  the  magneto- 
electric,  and  later  in  the  dynamo-electric  ma- 
chine. During  the  year  18G8  he  constructed 
two  electro-motors.  The  first — a  rough  model 
only — was  made  from  an  old  magnet,  some 
clock  wheels,  and  stray  pieces  of  iron  he  had 
picked  up  in  the  office.  This  model  worked, 
and  its  success  encouraged  him  to  have  a  larger 
one  constructed  under  his  direction.  Experi- 
ments with  the  first  model  proved  to  him  that 
a  galvanic  battery  would  be  too  cumbersome 
and  costly  a  means  of  producing  a  current  ever 
to  become  practically  useful,  and  he  then  en- 
deavored by  correspondence  to  find  out  the  pos- 
sibility of  procuring  large  power  machines. 
The  object  in  constructing  these  first  motors 
was  to  run  street  cars  in  San  Francisco.  Mr. 
Field's  efforts  to  obtain  a  dynamo-electric  ma- 


62 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


chine  were  unsuccessful  at  the  time.  In  1871 
he  associated  himself  with  Mr.  Geo.  S.  Ladd 
and  others  in  the  organization  of  the  Electrical 
Construction  and  Maintenance  Company,  of 
which  he  acted  for  nearly  seven  years  as  sec- 
retary and  electrician.  In  1877  he  went  to 
Europe,  and  there,  at  the  workshop  of  M.  Bre- 
guet  in  Paris,  he  saw  some  Gramme  machines, 
which  were  exactly  suited  to  the  purpose  of 
furnishing  a  current  for  his  projected  motor. 
On  his  return  from  Europe,  two  of  these  ma- 
chines were  ordered  by  Mr.  Ladd,  but  after  con- 
siderable delay  the  Californians  were  informed 
that  Breguet  would  not  send  the  machines,  be- 
ing afraid  of  invalidating  some  of  his  patent 
rights  in  the  United  States.  Upon  receipt  of 
this  information,  a  machine  was  immediately 
ordered  from  Siemens  Bros.,  of  London.  At 
last  their  hopes  seemed  about  to  be  realized  and 
the  long  cherished  project  of  applying  elec- 
tricity to  locomotion  was  in  a  fair  way  to  be 
practically  tested,  but  another  disappointment 
awaited  them.  The  hoped-for  dynamo  was  lost 
at  sea  on  the  way  to  San  Francisco.  Nothing 
daunted  by  this  misfortune,  they  promptly 
ordered  another  machine,  and  at  last,  in  the 
fall  of  1878,  it  arrived.  At  the  same  time  two 
Gramme  machines  were  placed  at  their  dis- 
posal by  the  Hon.  Milton  S.  Latham.  With 
these,  experiments  were  made  in  a  loft  on 
Market  street,  and  an  elevator  loaded  with 
1,500  pounds  of  coal  was  made  to  ascend  and 
descend  by  their  agency.  The  possibility  of 
moving  a  load  and  of  controlling  and  reversing 
the  motion  by  means  of  an  electric  current  sup- 
plied by  a  dynamo  machine  was  now  proved 
beyond  a  doubt.  In  February,  1879,  Mr.  Field 
elaborated  his  plans  for  an  electrical  railway 
and  made  drawings  of  a  motor,  which  is  sub- 
stantially the  same  as  that  afterward  put  in 
operation  by  him  at  Stockbridge.  In  May  of 
that  year  a  caveat  was  filed  by  him  in  the 
United  States  Patent  Office,  which  covered  a 
claim  for  an  electric  tramway  motor,  the  cur- 
rent to  be  supplied  by  a  stationary  source  of 
power  and  connected  with  the  rails.  By  means 
of  a  secondary  machine  on  the  motor  the  cur- 
rent would  be  converted  into  power  to  be  sup-, 
plied  to  the  axles  of  the  car  by  suitable  gear- 
ing, and  so  the  car  would  be  propelled.  The 
claim  also  covered  a  method  of  reversing  the 
motion  of  the  car  by  reversing  the  direction  of 
the  electric  current. 


"  This  was  the  very  first  official  record  of  a 
plan  for  a  dynamo-electric  railway.  In  July, 
1879,  at  the  solicitation  of  friends,  Mr.  Field 
came  to  New  York,  and  placed  the  matter  of 
filing  an  application  for  a  patent  in  the  hands 
of  his  old  friend,  Frank  L.  Pope.  This  applica- 
tion was  filed  March  10,  1880. 

'•  Up  to  this  time  the  electric  railway  was  all 
on  paper.  It  was  considered  advisable  by  Mr. 
Pope  that  a  working  model  should  be  con- 
structed and  operated,  so  in  May  of  that 
year  Mr.  Field  began  at  Stockbridge  the 
building  of  a  railway  and  an  electric  motor. 
The  machines  he  first  experimented  with 
proved  worthless,  and  he  was  obliged  to  stop 
work  until  he  could  procure  funds  to  buy 
others.  This  he  finally  succeeded  in  doing, 
and  in  1881  the  road  was  in  successful  oper- 
ation. Meantime  the  Siemens  Brothers  had 
been  experimenting  on  electric  railways  in 
Europe,  and  had  constructed  several  that 
worked  well  on  a  small  scale.  Mr.  Edison  had 
also  been  at  work  on  the  same  problem,  and 
built  his  well  known  little  railway  at  Menlo 
Park.  The  inventions  of  the  three  investi- 
gators clashed,  and  on  applying  for  patents 
they  came  in  collision.  It  was  soon  found  that 
the  application  of  Siemens  was  subsequent  to 
those  of  both  Edison  and  Field,  and  it  was 
thrown  out.  The  trial  between  the  two  re- 
maining competitors  was  long  and  tedious. 
The  testimony  was  taken  two  years  ago,  but 
it  was  only  last  week  that  the  final  decision, 
awarding  priority  of  claim  to  Field,  was  an- 
nounced. The  caveat  filed  in  1879.  with  its 
rude  accompanying  sketch,  was  shown  to  be, 
as  has  already  been  stated,  the  very  first  official 
record  of  a  plan  for  operating  an  electric  rail- 
way. Pending  the  result  of  the  contest  in  the 
Patent  Office,  a  consolidation  of  the  Field  and 
Edison  interests  was  effected  in  188:5,  and  the 
Electric  Railway  Company  of  the  United  States 
came  into  existence." 

The  company  here  named  was  organized 
about  the  beginning  of  May,  1883.  The  project 
of  exhibiting  at  the  Chicago  Railway  Exposi- 
tion of  that  year  had  been  entertained,  but  it 
was  not  until  two  weeks  before  the  opening  of 
the  exposition  that  it  was  definitely  decided 
that  the  electric  railway  should  form  one  of  its 
features.  Everything  remained  to  be  prepared. 
The  locomotive  was  scarcely  begun,  and  the 
track  was  not  laid.  But  the  work  was  put 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


63 


under  way  and  pushed  with  vigor.  It  is  need- 
less to  say  that  the  electric  railway,  under  the 
circumstances,  did  not  fairly  represent  the  in- 
ventions of  Messrs.  Field  and  Edison,  because 
the  short  time  allowed  to  complete  prepara- 
tions left  no  other  alternative  than  to  make 
use  of  such  electrical  apparatus  and  material 
as  could  be  readily  and  conveniently  procured 
in  the  market  without  stopping  to  inquire  too 
closely  into  its  fitness  for  the  purpose,  and  then 


force  of  about  seventy-five  volts,  with  a  cur- 
rent of  about  150  amperes,  through  its  normal 
circuit  resistance  of  .5  ohm.  Its  weight  was 
2,700  pounds.  The  locomotive  itself  is  shown 
in  Fig.  C3.  It  was  named  "  The  Judge,"  after 
Chief  Justice  Field,  the  uncle  of  its  designer. 
The  track  ran  around  the  gallery  of  the  main 
exhibition  building,  curving  sharply  at  either 
end  on  a  radius  of  fifty-six  feet.  Its  total  length 
was  1,553  feet,  or  nearly  one-third  of  a  mile. 


IF 

.:  •          "   ..'**.. • 

FIG.  63. — THK  EI.KCTRIC  LOCOMOTIVE,  "  THE  JUDGE. 


to  design  everything  else  to  suit  its  electrical 
and  mechanical  peculiarities.  Under  the  cir- 
cumstances, it  was  impossible  to  hope  for  great 
efficiency  or  economy  of  results.  It  was,  in- 
deed, a  matter  of  surprise  that  an  electric  rail- 
way was  produced  at  all  from  the  resources 
available  at  the  time;  and  the  execution  of  the 
novel  task  reflected  great  credit  on  Mr.  Frank 
B.  Rae  and  his  assistant,  Mr.  Clarence  L. 
Healy,  who  together  attended  personally  to  the 
many  details.  The  same  type  of  Weston  shunt- 
wound  machine  was  obtained  from  the  United 
States  Electric  Lighting  Company  for  gener- 
ator and  motor.  At  its  normal  speed  of  1,100 
revolutions,  the  machine  had  an  electromotive 


The  track,  Fig.  (54,  was  of  three-foot  gauge, 
and  had  a  central  rail  for  conveying  the  cur- 
rent, the  two  outer  rails  serving  as  the  return. 
In  order  to  secure  a  low  resistance  and  proper 
connections  between  all  the  rails,  a  precaution 
made  necessary  by  the  low  electromotive  force 
of  the  generator,  wires  were  laid  under  each 
rail.  The  inside  rail  was  wired  with  No.  6 
(B.  &  S.)  bare  copper  wire  and  the  outside  rail 
with  No.  8  iron  wire.  The  central  rail  was  also 
wired  with  No.  8  copper  wire.  A  good  contact 
was  made  with  each  rail  by  proper  fastenings 
at  the  joints  and  also  by  laying  the  wire  under 
the  rails  in  the  supporting  plates,  so  that  the 
weight  of  the  rail  rested  upon  it.  These  pre- 


64 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


totd  length  of  Track. 


FIG.  64. — TRACK  OF  ELECTRIC  RAILWAY,  CHICAGO 
EXPOSITION,  1883. 


FIG.  65. — "THE  JUDGE" — SIDE  ELEVATION. 


FIG.  66.— PLAN  VIEW  OF  '  THE  Ji  IX;K. 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


65 


cautions  practically  reduced  the  resistance  of    by  the  generator,  but  in  this  case  it  meant  a 

the  line  to  a  value  so  small  as  to  be  inconse-    reduction  of  one-third. 

quential. 


It  need  scarcely  be  said  that  if  the 
electromotive   force  of   the   current  used  had 


The  internal  construction  of  the  locomotive 
will  be  readily  understood  from  the  accompany- 


been  higher  these  precautions  would  not  have     ing  Figs.  65,  GO,  07,  and  08.     Fig.  65  shows  the 


FIG.  67. — HEAR  ELEVATION  OF  "  THE  JUDGE." 


been  required,  and  a  simple  connection  of  the 
rails  together  without  wires  would  have  sufficed. 
With  an  electromotive  force  of  300  volts,  for 
instance,  to  produce  the  same  current,  the  ad- 
dition of  .25  ohm  to  the  circuit  resistance  by 
the  rails  would  not  have  produced  a  very 
marked  lowering  effect  on  the  current  delivered 

9 


locomotive  in  side  elevation  with  its  cab  re- 
moved. Fig.  06  is  a  plan  view  of  the  same. 
These  figures  show  the  manner  of  transmitting 
the  power  from  the  armature  of  the  motor  to  the 
driving  wheels.  The  motor  was  placed  cross- 
wise upon  the  frame.  Its  armature  shaft  was 
coupled  to  an  extension  shaft  which  was  pro- 


66 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


longed  forward  and  transmitted  motion  by  means 
of  bevel  gearing  to  a  counter-shaft  carrying  two 
pulleys.  From  these  pulleys  the  power  was 
transmitted  by  means  of  belts  to  the  loose  pul- 
leys on  the  axle  of  the  drivers.  It  will  be  no- 
ticed that  this  arrangement  threw  the  greatest 
weight  directly  over  the  driving  wheels.  The 
gearing  up  of  the  armature  extension-shaft  to 
the  counter-shaft  was  made  so  as  to  reduce  the 
speed  three  times.  The  pulleys  on  the  counter- 
shaft were  twelve  inches  in  diameter,  the  driven 
or  loose  pulleys  on  the  axle  of  the  drivers  were 
twenty-six  inches  in  diameter,  and  the  car 
wheels,  or  drivers,  were  thirty  inches  in  diame- 
ter. The  maximum  speed  which  this  gearing 
would  produce  was  about  twelve  miles  per 
hour,  but  the  weakness  of  the  gallery  upon 
which  the  track  was  laid  made  it  necessary  to 
run  the  locomotive  at  a  lower  speed.  The 
average  speed  maintained  was  eight  miles  an 
hour,  the  armature  revolving  at  the  rate  of 
about  750  revolutions  per  minute. 

It  was  found  by  Messrs.  Rae  and  Healy  in 
their  preliminary  experiments  with  the  two 
machines  that  the  condition  of  best  efficiency 
of  the  generator  was  realized  when  the  motor 
had  attained  its  maximum  speed,  and  that  the 
power  developed  was  greater  at  that  time. 
From  this  they  inferred  that  the  proper  moment 
to  put  the  load  on  the  motor  was  when  it  had 
reached  its  greatest  velocity. 

The  mechanism  by  means  of  which  this  was 
accomplished  was  quite  ingenious  and  simple, 
as  seen  in  Fig.  67,  which  represents  a  rear  end 
elevation  of  the  locomotive  without  the  cab. 
The  loose  pulleys  G  G  ran  on  the  axle  of  the 
drivers  W  W,  as  previously  stated,  motion  be- 
ing transmitted  to  them  by  belts  from  the  pul- 
leys of  the  counter-shaft,  as  already  shown. 
F  F  Fl  Fl  were  cone  friction  pulleys  fitting 
into  the  interior  of  the  rim  of  the  loose  pulleys. 
These  friction  pulleys  revolved  with  the  shaft, 
being  connected  thereto  by  means  of  keys 
and  keyways.  which  were  loose,  however,  so 
that  the  friction  pulleys  could  be  free  to  slip 
lengthwise  on  the  axle  as  they  revolved.  The 
hub  of  each  friction  wheel  Fl  FI  carried  a  col- 
lar E  E  which  was  connected  by  arms  D  D  to 
a  lever  B  fulcrumed  at  C  on  a  projection  from 
another  collar  fitted  around  the  shaft.  The 
operation  of  this  form  of  friction  clutch  will  be 
readily  understood.  In  the  position  shown,  the 
friction  cones  F  F  F^  FI  are  removed  from  the 


pulleys,  which  are  free  to  move  loosely  upon 
the  axle.  But  upon  moving  the  lever  B  to  the 
right  the  friction  cones  are  both  moved  out- 
ward from  the  centre,  and  caused  to  engage 
the  inner  surface  of  the  pulleys,  and  thus  the 
motion  of  the  loose  pulleys  is  communicated  to 
the  drivers  W  W. 

As  already  stated,  the  central  rail  of  the 
track  formed  one  conductor  and  the  two  outside 
rails  R  R  the  other.  The  device  for  "picking 
up"  the  current  was  quite  ingenious,  and  is 
also  shown  in  Fig.  67.  It  consisted  of  a  kind 
of  inverted  vise  firmly  bolted  to  an  arm  H  H 
projecting  downward  from  the  frame  of  the 
locomotive.  The  jaws  N  N  of  the  vise  were 
each  perforated  with  three  holes  directed  ob- 


FK;.  68. — SPEED  REGULATOR. 

liquely  downward  and  inward,  through  which 
bundles  of  phosphor-bronze  wire  passed,  being 
securely  fastened  and  held  by  a  screw  0.  A 
spring  S  extending  between  the  arms  of  the 
vise  served  to  bring  the  two  brushes  M  M  into 
close  and  sure  electrical  contact  with  the  cen- 
tral rail  P.  The  wire  being  stiff  and  firm,  the 
contact  was  equally  certain  whether  the  loco- 
motive was  moving  forward  or  backward. 

An  important  feature  of  this  electric  locomo- 
tive was  the  means  by  which  the  speed  could 
be  regulated  at  pleasure  by  a  "  throttle- valve  " 
arrangement  resembling  that  found  in  every 
American  locomotive,  and  which  answers  tilt 
same  function;  namely,  to  control  the  amount 
of  force  put  in  action.  The  nature  of  the  device 
was  as  simple  as  it  was  efficient,  and  consisted 
simply  in  a  lever,  Fig.  08,  by  the  motion  of 
which  the  resistance  of  a  suitable  rheostat 
could  be  thrown  in  and  out  of  the  main  cir- 
cuit with  the  evident  result  of  controlling  the 
amount  of  current  flowing  therein.  The  lever 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


67 


was  placed  horizontally  and  could  move  over 
contact  segments  disposed  in  a  circle.  These 
segments  were  insulated  from  each  other,  but 
they  were  connected  by  coils  of  iron  wires  so 
as  to  make  a  certain  resistance,  and  possessing 
sufficient  area  of  section  to  remain  cool.  Thus, 
when  the  lever  was  in  the  position  shown  in 
the  figures,  there  was  no  resistance  included  in 
the  circuit.  When  the  lever  was  moved  for- 
ward to  the  next  segment,  the  resistance  added 
to  the  circuit  was  .1  ohm.  On  moving  to  the 
next  the  resistance  added  was  .2  ohm,  and  so 
on,  the  amount  of  resistance  included  in  circuit 
when  the  lever  touched  each  segment  being  in 
Fig.  08  indicated  by  the  figures  thereon.  The 
rheostat  comprised  two  Edison  B  lamps  of  85 
ohms  each,  so  that  the  total  resistance  when 
the  lever  touched  the  last  segment  was  174 
ohms.  It  will  be  readily  understood  that  by 
means  of  this  device  the  amount  of  current  in 
the  main  circuit  could  be  easily  varied. 

The  high  resistance  necessary  at  starting  to 
cause  the  magnetic  field  of  the  generator  to 
magnetize  itself  was  readily  afforded  by  this 
rheostat  on  closing  the  circuit.  Another  in- 
teresting feature  of  the  Chicago  electric  loco- 
motive was  the  device  by  means  of  which  the 
current  was  reversed  at  the  motor  when  it  was 
desired  to  make  the  locomotive  move  back- 
ward (Fig.  GO).  The  lever  J  caused  the  wheel 
HHto  turn  on  the  armature  shaft  G.  This 
wheel  geared  with  two  wheels  E  F,  to  which 
were  fastened  arms  C  C,  D  D.  These  arms 
carried  brush-holders  and  brushes  At  A.,  B{  Bf 
The  function  of  the  device  was  simply  to 
change  the  relative  direction  of  the  current 
through  the  armature  of  the  motor.  In  the  po- 
sition shown  in  the  figure  the  positive  brush  B2 
touched  the  commutator  at  the  left-hand  side, 
while  the  negative  brush  A2  touched  it  at  the 
right-hand  side.  On  moving  the  lever  J  as  far 
as  K,  the  brushes  A2  7?=  broke  contact.  In  this 
condition  the  motor  was  out  of  the  circuit  and 
received  no  current.  This  is  just  the  same  as 
when  the  reversing  lever  of  a  steam  locomo- 
tive is  moved  half  way,  thus  cutting  off  the 
steam  entirely  by  preventing  the  motion  of  the 
slide-valve.  On  moving  the  lever  still  further, 
the  brushes  At  Bt  came  in  contact  with  the 
commutator  of  the  motor,  so  that  the  positive 
brush  B!  touched  the  right-hand  side  of  the 
commutator  and  the  negative  brush  Al  the  left- 
hand  side,  instead  of  the  opposite.  The  re- 


sult was  necessarily  a  reversal  of  the  direction 
of  rotation  of  the  armature  of  the  motor. 

The  locomotive  was  also  provided  with  an 
electric  bell.  This  bell  had  a  resistance  of 
350  ohms,  and  was  rung  by  a  switch  which 


FIG.  o9. — RKVKRSING  MECHANISM. 

placed  it  in  parallel  circuit  with  the  motor.  Its 
high  resistance  prevented  the  diversion  of 
the  current  from  the  motor  in  any  appreciable 
quantity. 

The  locomotive  was  twelve  feet  long  and  five 
feet  wide.  Its  total  weight  was  about  three 
tons.  It  was  intended  to  be  run  with  two 


68 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


69 


passenger  cars,  but  it  was  found  upon  inspec- 
tion that  the  gallery  was  too  weak  to  stand  the 
strain.  Even  after  the  gallery  had  been 
strengthened,  it  was  not  deemed  expedient  to  ex- 
ceed a  speed  of  nine  miles  an  hour. 

The  Chicago  electric  railway  was  the  first 
constructed  in  this  country  for  business  pur- 
poses, and,  considering  the  .short  lease  of  active 


run  in  all  118J  hours  and  440.24  miles.  It  car- 
ried 20,805  passengers.  It  was  afterwards  sent 
to  the  Louisville  Exposition  during  the  same 
year,  and  there  carried  a  large  number  of 
passengers. 

Mr.  Thos.  A.  Edison's  work  in  electric  railroad- 
ing dates  back  to  the  spring  of  1880,  although 
his  ideas  on  the  subject  had  been  made  known 


Fiu.  71. — KAISLY  EDISON  KLKCTIUC  LOCOMOTIVE. 


life  which  was  left  to  it  after  it  was  finally 
completed  and  put  in  operation,  its  success  was 
most  surprising.  Owing  to  delay  in  receipt  of 
the  report  of  the  engineer  intrusted  with  the 
task  of  strengthening  the  gallery,  the  road  was 
not  permitted  to  operate  for  business  until  June 
9,  1883,  but  experimental  trips  of  the  electrical 
locomotive  were  made  daily  from  June  2. 

Upon  June  5  "The  Judge"  and  its  attached 
car  loaded  with  sixteen  passengers  was  started 
around  the  track.  The  railway  was  opened  for 
business  on  June  '.)  and  closed  June  23,  having 


at  least  a  year  earlier.  In  1880,  he  built  a  track 
at  Menlo  Park,  N.  J.,  near  his  laboratory.  This 
line  was  less  than  half  a  mile  in  length,  and  no 
special  pains  were  taken  in  the  preparation  of 
the  road-bed.  The  early  locomotive  employed  is 
shown  somewhat  roughly  in  Figs.  70  and  71. 
The  generator  and  motor  were  of  a  type  then 
made  by  Mr.  Edison,  but  not  now  in  use.  The 
current  was  led  to  the  track  by  two  copper 
wires,  one  to  each  of  the  rails,  which  were  thus 
positive  and  negative,  and  were  insulated  from 
each  other.  The  armature  of  the  motor  was 


70 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


connected  in  the  usual  manner  with  the  driving 
wheels,  and  made  four  revolutions  to  their  one. 
Fig.  72  shows  the  Edison  locomotive  as  after- 
wards improved. 

Towards  the  close  of  1883,  the  experiments  of 
Mr.  Leo  Daft,  the  electrician  of  the  Daft  Electric 
Light  Company,  began  to  attract  attention;  and 
the  ability  and  perseverance  since  exhibited  by 


curve  having  a  radius  of  about  290  feet;  but 
the  tests  as  a  whole  gave  great  encouragement 
to  Mr.  Daft's  friends. 

We  show  in  Figs.  74  and  75  a  plan  and  eleva- 
tion of  the  locomotive  "  Ampere,"  used  on  the 
Saratoga  road,  and  still  in  operation  elsewhere. 
It  is  about  ten  feet  in  length,  and  rests  upon 
four  wheels.  The  motor  is  situated  at  the  rear 


FIG.  72. — IMPROVED  EDISON  ELKCTKIC  LOCOMOTIVE. 


Mr.  Daft  in  the  various  application  of  electric 
motors  have  given  him  great  and  deserved 
prominence  to-day.  At  first  the  trials  of  the 
Daft  motor  were  made  on  the  grounds  of  the 
company's  works  at  Greenville,  N.  J.,  and  there 
proving  successful  they  were  renewed  on  the 
Saratoga  and  Mount  McGregor  Railroad  in 
November  of  1883.  The  line  is  about  twelve 
miles  long,  and  abounds  in  sharp  curves 
and  steep  grades.  During  its  first  trip  there, 
the  motor  "  Ampere,"  Fig.  73,  being  too  light 
for  the  pull  given  it,  jumped  the  track  on  a 


end  of  the  platform,  and  is  incased  in  a  box  to 
prevent  injury  from  dust. 

The  armature  of  the  motor  has  a  special 
construction  in  order  to  deliver  the  large  current 
required.  Mr.  Daft  achieves  this  by  grouping 
equidistant  along  the  periphery  of  his  annular 
revolving  armature  as  many  superposed  bob- 
bins as  the  case  in  point  demands,  and  fagoting 
their  terminals  before  leading  them  to  the  seg- 
ments of  the  commutator  to  which  they  respect- 
ively belong.  Each  one  of  a  group  of  bobbins, 
on  the  armature,  crosses  the  magnetic  field  at 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 

approximately  the  same  instant,  and  the  cur- 
rent developed  in  them  collectively  is  of  a 
potential  due  to  their  few  convolutions  and  of 
a  quantity  proportional  to  the  enlarged  channels 
of  escape. 

At  each  end  of  the  armature  shaft  there  is 
keyed  a  pulley,  from  which  belts  run  to  the 
large  central  pulleys  mounted  on  the  counter- 
shaft, which  is  situated  midway  between  the 
driving  wheels.  Another  set  of  belts  connects 
the  latter  with  the  counter-shaft,  and  the  reduc- 
tion of  speed  from  the  armature  pulleys  to  the 
drivers  is  in  the  ratio  of  eight  to  one.  The  two 
small  wheels  shown  as  resting  on  the  rail  are 
phosphor-bronze  contact-wheels;  they  bear  upon 
the  central  rail,  and  through  them  the  current 
is  taken  up.  They  are  fixed  upon  springs  so 
arranged  that  they  can  mount  any  small  ob- 
stacle on  the  rail;  but,  being  two  in  number,  ^ 
one  of  them  is  always  in  contact,  thus  insuring  9 
an  uninterrupted  current.  2 

The  driver  of  the  locomotive  is  provided  with  I 
a  seat,  and  situated  directly  in  front  of  him  are  > 
three  switch-boxes.  The  one  toward  the  right  •* 
is  the  main  switch  by  which  the  current  can  be  j? 
turned  on  or  off.  The  regulation  of  speed  in 
the  "  Ampere  "  is  effected  entirely  by  means  of  2 
the  "multi-series  switch,"  constituting  the  mid-  _, 
die  box,  which  is  so  arranged  as  to  effect  an  £ 
almost  endless  variety  of  changes  in  the  inten-  2 
sity  of  the  field  of  force,  without  the  use  of  H 
idle  resistance.  In  order  to  accomplish  this,  * 
some  iron  wire  is  employed  in  the  outer  coils  £ 
of  the  field  magnets  so  as  to  obtain  the  required  =• 
resistance  without  too  greatly  exceeding  the  3 
magnetic  limit.  '- 

The  brakes  of  the  "Ampere"  are  controlled 
by  the  third  switch  shown,  and  a  mere  turn  of 
the  hand  causes  them  to  act  with  any  required 
degree  of  intensity.  The  brakes  themselves 
are  of  the  so-called  "  pendulum  "  type.  As  will 
be  seen,  they  are  suspended  from  the  frame  of 
the  car  and  swing  freely  on  a  bolt  passed 
through  an  eye  at  their  upper  ends.  The  sus- 
pended frame  carries  an  electro-magnet  wound 
with  stout  wire,  and  when  the  current  is 
switched  into  the  latter  the  magnet  immedi- 
ately follows  the  attraction  of  the  wheel,  press- 
ing against  it  and  exerting  a  powerful  grip. 
Situated  at  the  side  of  the  driver  there  will  also 
be  seen  a  lever,  by  means  of  which  the  locomo- 
tive can  be  sent  forward  or  reversed  at  will. 
This  is  accomplished  through  the  medium  of 


71 


72 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


four  brushes  arranged  about  the  commutator 
and  placed  equidistantly  apart.  The  lever  has 
two  rods  at  its  lower  extremity,  which  connect 
with  two  brushes  each,  and  by  this  means  either 


starting  point.  The  track  was  laid  with  thirty- 
five  pound  rails,  in  addition  to  which  a  central 
track  of  similar  rails  was  laid  upon  blocks  of 
hard  wood,  saturated  with  resin,  which  were 


FIG.  74. — PLAN  OF  "AMI-EKE." 


pair  can  be  put  in  contact  with  the  commutator 
with  the  result  above  mentioned. 

From  the  above  description  it  will  be  seen 
that  the  locomotive  presents  all  the  features  of 
a  well  executed  system,  and  some  details  of  the 
test  at  Saratoga,  mentioned  above,  will  there- 


spiked  down  to  the  ties  at  intervals  of  six  or 
eight  feet;  upon  this  ran  the  phosphor-bronze 
contact-wheels. 

The  generators  consisted  of  two  of  Mr.  Daft's 
old  type  No.  8  series  machines,  which  were 
operated  about  100  yards  from  the  track  by  a 


FIG.  75. — ELEVATION  OF  "AMPERE." 


fore  prove  of  interest.  On  that  occasion  the 
track  upon  which  the  "  Ampere  "  ran  was  about 
one  and  one-quarter  miles  long,  being  part  of 
the  main  track  of  the  Saratoga  and  McGregor 
Railroad,  and  included  a  very  sharp  curve  and 
grade  combined,  about  one  mile  away  from  the 


twenty-five  horse-power  Buckeye  engine  situ- 
ated in  the  Saratoga  Rubber  Works.  The 
Daft  machines  will  be  found  fully  described 
in  Chap.  IX. 

The  calculated  resistance  of   the    line  was 
about  two  ohms.     The  actual  resistance  could 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


73 


not  be  measured,  owing  to  the  continual  earth 
disturbances.  By  other  tests,  however,  it  was 
evidently  very  low.  The  resistance  of  insula- 
tion between  central  and  outside  rails,  when 
the  ground  was  wet  from  a  recent  rain,  reached 
about  130  ohms,  showing  a  leakage,  from  that 
source,  of  about  one  and  one-half  per  cent, 
of  current  with  motor  under  maximum  load. 
The  resistance  of  motor,  as  given  below,  is 
taken  while  at  rest;  it  is  of  course  higher  with 
the  motor  in  motion,  as  will  be  readily  under- 
stood. 

The  following  are  some  of  the  results  of  the 
tests  made  at  that  time: 

Internal  resistance  of  primary  machines  in  par- 
allel,      0.42  ohms. 

Resistance  of  motor from  1.04  to  5      " 

"  "  line  (calculated), 0.2       " 

"  track-insulation 130       " 

"  "  motor   arranged   for    low   speed 

and  great  traction  at  start — at  rest,  .  .  .  3.10  " 
Resistance  of  motor  arranged  for  highest  duty,  1.15  " 
Mean  electromotive  force  over  high  resistance 

shunt  at  start, 100  volts. 

Electromotive  force,  with   lowest  external  re- 
sistance employed 130       " 

Current,  when  ascending  grade, 80  amperes. 

Revolutions  per  minute, 1050 

The  actual  performance  of  the  "  Ampere " 
consisted  in  hauling  an  ordinary  railway  car 
weighing  ten  tons,  containing  sixty-eight  per- 
sons in  addition  to  the  motor,  which  weighed 
two  tons,  and  had  five  persons  upon  it.  The 
speed  obtained  was  eight  miles  per  hour  upon 
a  track  having  a  gradient  of  ninety-three  feet 
to  the  mile,  and  included  a  curve  of  about  20°. 
This  showed  a  maximum  duty  of  about  twelve 
horse  power,  and,  although  the  actual  efficiency 
was  not  determined,  it  ought  to  be  mentioned 
that  the  twenty-five  horse-power  engine,  which 
actuated  the  primary  machines,  was  also  doing 
other  duty  in  the  factory. 

During  1884  Mr.  Daft  built  and  equipped  a 
small  line  on  one  of  the  piers  at  Coney  Island. 
This  did  not  go  into  operation  until  part  of  the 
season  had  passed,  but  it  carried  38,000  pas- 
sengers. A  little  later  another  Daft  road  at  the 
Mechanics'  Institute  Fair  in  Boston  carried  be- 
tween 4,000  and  5,000  passengers  weekly  for 
more  than  a  month.  Its  motor  "  Volta  "  was 
then  taken  to  fie  New  Orleans  Exposition,  where 
a  Daft  road  was  put  in  operation  between  the 
main  building  and  the  government  building,  a 
10 


distance  of  nearly  a  fifth  of  a  mile.  It  was 
there  run  regularly  by  a  No.  4  Daft  generator, 
driven  by  a  Payne  engine,  and  again  carried 
several  thousand  passengers. 

In  the  early  part  of  the  spring  of  1885  the 
Baltimore  Union  Passenger  Railway  Company, 
hearing  of  the  rapid  progress  of  the  Daft  Elec- 
tric Light  Company  with  its  system  of  electric 
railways,  and  wishing  to  increase  its  carrying 
capacity,  investigated  the  matter.  Satisfied 
with  the  completeness  of  the  system,  an  order 
was  at  once  given  to  construct  two  motors  and 
equip  the  Hampden  branch  of  the  lines  named. 

It  was  some  time,  however,  before  definite 
plans  were  settled  upon;  but  about  the  middle 


FIG.  76. — MKTHOD  OK  RAIL  INSULATION-. 

of  April  work  was  begun  both  at  Baltimore  and 
at  the  Daft  works.  On  June  10  the  first  motor 
was  shipped.  The  Baltimore  Union  Passenger 
Railway  Company,  Edgar  M.  Johnson  presi- 
dent, T.  C.  Robbins  general  manager,  is  one 
of  the  largest  in  the  city.  It  operates  twenty- 
five  miles  of  roads,  and  has  within  its  stables 
nearly  400  horses.  The  Hampden  branch  is  just 
two  miles  long,  runs  through  the  villages  of 
Hampden,  Mt.  Vernon,  and  Woodbury,  aggre- 
gating some  15,000  inhabitants,  and  is  one  of 
the  hardest  bits  of  line  the  company  operates. 
Starting  from  the  main  terminus  on  Hunting- 
don avenue,  there  is  scarcely  300  feet  of  level 
road  the  entire  length.  The  village  of  Wood- 
bury,  though  not  two  miles  distant,  is  150  feet 
higher  than  Baltimore.  Grades  and  curves 


74 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


constitute  the  main  features:  in  fact  Mr.  Daft 
appears  to  disdain  an  ordinary  track  on  the 
level.  The  heaviest  grade  on  a  tangent  is  319 
feet,  and  on  a  curve  352  feet  per  mile.  The 
sharpest  curve  has  a  radius  of  but  50  feet,  the 
largest  89  feet. 

To  equip  this  road  the  joints  of  the  outer 
rails  were  perfected,  and  a  third  rail,  an  ordi- 
nary 25-lb.  T  rail  similar  to  the  outer  rails,  was 
laid,  with  the  Daft  patent  insulator,  mid- 
way between  the  outer  rails. 

The  insulator.  Fig.  ~6.  consists  of  an  iron 
shoe  of  diamond  shape,  eight  inches  long,  three 


Fir..  77.—  DAFT  MOTOR. 


and  one-half  inches  wide  and  one-quarter  inch 
thick,  with  two  converging  ways  upon  one  of 
its  surfaces. 

Wedged  between  these  ways  is  a  round  block 
of  wood  of  truncated  cone  shape,  with  a  height 
of  two  and  one-half  inches.  Upon  this  block  is 
screwed  a  round  iron  cap.  This  is  four  and 
one-half  inches  in  diameter  and  two  inches 
deep.  Coming  within  three-quarters  of  an  inch 
of  the  iron  shoe,  it  thoroughly  protects  the 
wood  block.  The  rail  placed  on  the  cap  is  held 
in  position  by  two  bolts  screwed  into  the  cap. 
The  difficulties  of  constructing  such  a  work,  it 
being  all  entirely  new,  were  many,  but  they 
were  met  and  successfully  overcome. 

The  centre  rail  forms  the  outgoing  lead,  the 
two  outer  rails  with  the  ground  being  the  re- 
turn. The  resistance  of  such  a  line  averages 
iti-«n  .3  of  an  ohm.  with  perfect  joints.  At 


the  main  terminus  a  new  building,  forming  one 
room  -20  by  40  feet,  was  built  for  the  engine  and 
dynamo.  The  engine  is  a  l?>  by  ->4  inch  Atlas 
engine,  made  at  Indianapolis.  The  boiler  and 
all  fittings  are  from  the  same  firm. 

The  dynamo  is  one  of  the  Daft  Company's 
largest.  Its  total  weight  is  4.200  pounds  and  its 
maximum  capacity  is  300  amperes  at  K>5  volts 
electromotive  force.  A  nine-inch  double  belt 
connects  direct  from  the  ten-foot  fly-wheel  on 
the  engine  to  a  fifteen-inch  pulley  on  the  dyn- 
amo. Switches,  regulators,  automatic  cut- 
outs, and  all  other  safety  devices  necessary  for 
a  complete  system  were  put 
in.  as  precautionary  measures 
against  every  possible  form  of 
danger  or  trouble. 

The  construction  and  appear- 
ance of  the  motor  for  this  line 
is  fairly  represented  by  Figs. 
??  and  T>.  Its  name,  as  will 
be  seen,  recalls  the  important 
connection  of  Professor  M 
with  the  city  of  Baltimore. 

Over  all.  the  motor  measures 
1-2  ft,  6  in.  by  .;  ft.  OJ  in.  The 
frame  is  constructed  of  ?|  by 
19  in.  ash.  bolted  together  and 
braced  with  four-inch  angle 
iron.  The  inside  dimensions 
are  9  ft.  1}  >»-  Kv  5  ft-  ni  in- 
The  wheels  are  standard  car 
wheels,  but  with  specially  deep 
flanges  and  wide  treads:  they 
are  thirty  inches  in  diameter  and  have  five  foot 
centres. 

The  cab  is  built  in  the  ordinary  manner.  It 
is  finished  inside  with  ash  and  black  walnut. 
and  is  very  neat  and  substantial.  The  re- 
ceiving machine  is  a  compound  series  motor 
capable  of  delivering  eight  horse  power.  Its 
total  weight  is  1.100  pounds,  the  armature  being 
196  pounds.  The  compound  nature  of  the  field 
permits  of  a  wide  range  of  resistances,  and  hence 
of  magnetic  strength  of  field.  As  the  armature- 
speed  depends,  in  a  certain  sense,  upon  this  field, 
a  perfect  means  of  regulation  of  speed  is  obtain- 
able. 

Motion  from  armature  shaft  to  car  wheels  is  ob- 
tained by  internal  gears.    Upon  each  end  of  this 
shaft  a  three-inch  phosphor-bronze  gear  is  keyed. 
These  engage  with  large  gears,  twenty-seven 
inches  in  diameter,  fastened  to  the  axle  of  the 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IX  AMERICA. 


- 


By    this    arrangement    the 
of  the  armature  is  xtfliacd  practioallv 
:  directly  upon  the  periphery  of  the  dri  v- 

The  speed  of  armature  to 
to  one.    Therefore  as  the 

509    revolutions    to .  the    mile. 

The  ratio  of  peripheral  speeds,  howww,  of 
armature  to  drivers  is  as  3.??  to  1. 

As  high  speed  is  the  normal  condition  of  an 
armature,  no  real  sacrifice  is  made  to  gain 

leverage.  The  speed  of  armature  for 
eight  miles  an  hoar,  the  limit  the  law 
allows,  is  6ia  To  take  up  all  bark-lash 
of  gears,  the  motor  is  arranged  with 
pivoting  bearings  at  one  end  and  a 
regulating  screw  at  the  other,  both 
resting  upon  heavy  pieces  of  rubber. 
This  pivoting  arrangement  is  again 
advantageous  in  case  of  repairs,  or  in- 
spection, through  accident;  the  large 
gears  being  held  in  place  by  means  of 
a  set  screw  and  long  spline.  On  loosen- 
ing the  set  screw,  they  can  be  easily 
removed  along  on  the  axle,  freeing 
the  small  gears.  The  motor  then  can 
easily  be  raised  to  a  vertical  position 
allowing  free  inspection.  The  total 
weight  of  the  -  Morse  "  is  about  4.AO 
pounds. 

The  wiring  and  controlling  mechan- 
ism is  equally  as  simple  and  substan- 
tial. No.  4  B.  &  S.  underwriter's  wire 
is  used  throughout.  It  is  run  in 
grooved  sheathings,  and  covered  so 
that  no  wire  is  to  be  seen  excepting 
at  the  motor.  Every  precaution  has 
from  the  first  been  taken  to  obviate  any  danger 
arising  from  moisture  or  short-circuits. 

The  controlling  device  consists  of  four  heavy 
brushes  bearing  upon  a  stout  frame  of  soap- 
stone,  carrying  broad  and  properly  shaped  con- 
tact pieces.  This  whole  ^s  enclosed  in  an  S  in. 
by  10  in.  iron  box.  with  an  ordinary  engineer's 
handle  and  guide. 

Four  movementsare  made,  controllingtheoom- 
biuations  of  the  field  magnets,  which  vary  from 
:o  o.To  ohms.  The  resistance  of  the  arma- 
ture is  .-.U  of  an  ohm.  By  proper  connections 
with  the  switch,  it  can  be  readily  seen  that  the 
motor  can  be  slowly  and  easily  started,  stopped, 
or  run.  By  turning  a  small  handle  placed  just  to 
the  left  of  the  main  switch,  either  to  the  right  or 


left,  one  of  two  pairs  of  1 
on  the  coaamntator.  thus  giving  the  directive  mo- 
tion to  the  arnwnore,  and  obviously  to  the  car. 

.other  switch  just  to  the  right  of  the  main 
switch  is  a  dead  cat-off  controlling  the  «*««i« 
current  coming  from  the  contact  wheel.  This 
is  placed  andcraeath  the  car,  and  consists  of  a 
heavy  f ourteen-inch  wheel  of  phosphor-hronae, 
free  to  slide  four  inches  to  the  right  or  left,  and 
rotating  freely  upon  its  shaft  Adeepgroov  i 
cut  into  the  rim,  fitting  the  centre  rail.  By  a 


FIG.  78.  —  DTTAHS  or  THE  MOTOK  - 


lever  and  a  heavy  spring  a  constant  pressure 
tends  to  keep  the  wheel  down  on  the  rail.  By 
this  arrangement  the  wheel  can  adapt  itself  to 
every  curve  or  change  of  level  of  the  rail.  An 
ordinary  hand  brake  is  placed  in  the  car  just  to 
the  left  of  the  switches.  By  this  handy  ar- 
rangement. one  man.  with  a  little  practice,  can 
easily  manipulate  the  switches  and  brake,  and 
so  control  the  car. 

It  may  be  here  stated  that  for  much  of  the  in- 
formation given  of  the  Daft  system,  we  are  in- 
debted to  Mr.  G.  W.  Mansfield,  to  whose 
efficient  hands  Mr.  Daft  has  generally  intrusted 
the  execution  of  his  plans. 

This  equipment  went  into  service  on  August 
-  -  from  when  until  now  the  road  has  been 


76 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


dependent  upon  electricity  as  its  sole  motive 
power. 

During  the  first  six  months  of  operation  sev- 
eral storms  of  peculiar  severity  visited  the 
region,  but  contrary  to  the  predictions  of  all 
the  visiting  electricians  the  road  did  not  suffer 
any  more  interruption  to  travel  than  was  ex- 
perienced on  ordinary  roads  from  the  same 


drivers  that  the  service  is  better  at  such  times 
than  in  fair  weather. 

The  road  was  at  first  supplied  with  two 
motors  only,  the  "  Morse  "  above  described  and 
the  "  Faraday,"  but  these  being  found  insuffi- 
cient, both  in  size  and  number,  for  the  greatly 
increased  traffic,  the  more  powerful  motors 
•'Ohm"  and  "  J.  L.  Keck"  were  added  early 


•~""\  *-, 

•#•&#. 
. 


FIG.  79. — CI;RVE  ox  THE  BALTIMOKK  KI.KCTRIC  STRKKT  RAILWAY. 


cause.  Several  times  parts  of  the  track  have 
been  actually  submerged  by  rain,  when  the 
spectators  have  been  treated  to  the  extraor- 
dinary spectacle  of  an  electric  motor  hauling  a 
heavily  loaded  car,  with  the  flanges  of  the 
driving  wheels  deep  in  the  water!  At  such 
times,  of  course,  the  insulation  was  somewhat 
impaired,  but  never  so  much  as  to  cause  any 
marked  change  either  in  the  speed  and  capacity 
of  the  motors  or  the  load  on  the  station  dynamo. 
Indeed  it  is  a  cherished  illusion  of  the  motor 


in  188C,  and  the  trains  are  now  despatched  at 
intervals  of  twenty  minutes,  instead  of  half 
hourly,  as  before. 

Each  motor  performs  an  average  daily  run  of 
seventy-five  miles,  which,  considering  the  ex- 
traordinary grades  and  curves  of  the  road,  is 
very  heavy  duty  for  a  mechanical  tractor.  The 
General  Manager  of  the  Baltimore  Union  Pas- 
senger Railway  Company,  Mr.  T.  C.  Robbins. 
has  made  many  improvements  in  the  road  since 
the  introduction  of  electricity,  and  has  through- 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


77 


out  shown  a  rare  intelligence  which,  together 
with  his  enthusiastically  progressive  tempera- 
ment, has  largely  contributed  to  the  successful 
prosecution  of  the  work.  A  late  survey  of  the 
road  shows  the  heaviest  grade  to  he  that  enter- 
ing Roland  avenue,  about  one  and  one-half  miles 
from  the  station,  of  348  feet  per  mile  on  a  curve 
of  75  feet  radius,  but  there  are  several  gradients 
of  over  250  feet  per  mile,  and  curves  ranging 


As  a  test  for  himself,  Mr.  Robbins  once  sent  to  the 
city  for  one  of  their  heaviest  cars,  ....  Ibs.  5,100 

And  carried  a  load  of  eighty-one  persons  over  the 

road  (say  81  X  125  pounds), His.  10,125 

The  weight  of  the  motor  used  was     ....     Ibs.       4,5(10 

Total, Ibs.     19,725 

Thus  he  says  that  10,725  pounds  were  carried  over 

the  road  by  one  motor  of Ibs.       4,500 


FIG.  80.— OVERHEAD  CONDUCTOR  ON  BALTIMORE  RAILWAY. 


from  40  to  90  feet  radius.  Fig.  79,  an  accurate 
reproduction  of  a  photograph,  represents  the 
motor  "  Morse "  on  the  curve  No.  5,  which 
combines  a  gradient  of  275  feet  with  a  curve  of 
89  feet  radius.  Mr.  A.  H.  Hayward,  the  elec- 
trician in  charge,  also  superintended  the  Daft 
Electric  Railroad  at  New  Orleans.  It  is  now 
proposed  to  extend  the  line,  with  overhead  con- 
veyance of  the  current. 

As  some  figures  may  be  asked  for,  the  fol- 
lowing will  be  found  of  interest.  They  were 
published  several  months  ago: 


His  engine  and  boiler  cost,  approximately,  ....    $2,400 
His  two  motors  cost,  approximately,  $3,000  each,     .      6,000 


Total, $8,400 

There  is  also  the  expense  of  conducting  rails 
and  wires,  insulation,  protection,  etc. 

His  expense  of  running  per  day  is   1J  tons  of  soft 

coal, •     .     .     .     .      $4.75 

Engineer  and  fireman  at  power  station 4  50 


Or,  excepting  oil,  waste,  wear  and  tear,  per  day,     •v!i  '_'"> 


78 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


z 

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O 

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CO 

6 


Tlie  above  represents  the  cost 
of  his  power,  and  equals  the 
work  of  thirty  horses  per  day. 
The  average  receipts  from  the 
cars  carried  by  the  two  motors 
are  $18  per  day,  and  he  has 
taken  (on  a  Sunday)  total  re- 
ceipts of  $8(!  in  one  day. 

As  the  present  work  goes  to 
press,  extensions  and  improve- 
ments are  being  made  on  the 
line.  Fig.  80  represents  the  new 
overhead  conductor  attachment 
which  has  recently  been  added 
to  the  Daft  motors  on  the  Balti- 
more &  Harnpden  Electric  Rail- 
road. As  will  be  seen  by  ref- 
erence to  the  cut,  the  contact 
mast  is  so  attached  as  to  be 
readily  operated  from  the  in- 
side by  the  engineer;  this  was 
deemed  necessary  as  the  over- 
head conductors  are  at  present 
only  used  at  street  crossings, 
thus  leaving  the  track  at  such 
places  free  from  the  third  rail 
and  the  raised  guard,  which 
were  found  to  be  objectionable. 
The  manner  of  connecting  the 
motors  with  the  overhead  con- 
ductor for  the  California  rail- 
roads, now  being  equipped  by 
the  Daft  Company,  differs  in 
some  respects  from  that  shown 
in  the  engraving,  especially  in 
the  manner  of  completing  the 
circuit  to  the  motor;  but  as  this 
plan  has  not  yet  been  put  in 
operation  no  further  reference 
need  now  be  made  to  it.  As  an 
instance  of  the  continued  suc- 
cessful working  of  the  Balti- 
more road,  it  is  worthy  of  note 
that  on  the  three  recent  holi- 
days, the  3d,  4th,  and  5th  of 
July,  upward  of  7,000  passen- 
gers were  carried,  or  over  3. 1  on 
more  than  by  horses  for  the 
same  time  last  year.  From  fig- 
ures supplied  by  Mr.  T.  C.  Rob- 
bins,  it  appears  that  the  line  has 
carried  31,007  more  passengers 
than  it  did  with  horses  during 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 

a  like  period  of  nine  months, 
and  that  the  cost  per  passenger 
lias  been  only  l.OO  cents,  as 
compared  with  3.01,  or  .83  cents 
per  passenger  mile  as  compared 
with  1.55  cents  with  horses. 
The  cost  of  horse  power  per  day 
was  $18;  the  cost  of  electric 
power  is  *!•>. 

It  may  he  safely  asserted  that 
few  engineering  events  within 
the  last  few  years  have  at- 
tracted more  popular  and  pro- 
fessional attention  than  the 
trials  of  electricity  as  a  mo- 
tive power  on  the  elevated  rail- 
ways of  this  city.  The  daily 
papers  printed  columns  regard- 
ing the  event,  and  a  number 
of  illustrated  papers  produced 
illustrations  of  the  Daft  motor 
put  upon  the  tracks. 

Before  entering  into  a  de- 
scription of  the  system,  as  it  is 
operated,  it  may  be  well  to  re- 
call the  events  which  led  up 
to  the  present  state  of  affairs. 

The  idea  of  running  the  ele- 
vated railway  trains  by  elec- 
tricity was  broached  several 
years  ago,  the  many  strong 
points  in  its  favor,  over  steam, 
being  pointed  out.  Nothing, 
however,  was  done  in  the  mat- 
ter beyond  its  mere  discussion, 
until  the  early  part  of  1885, 
when  at  a  meeting  of  the  vari- 
ous electric  motor  companies, 
an  attempt  was  made  to  con- 
solidate their  interests,  and  to 
test  the  motors  of  the  various 
companies  represented.  Acorn- 
mission  was  to  be  appointed 
(Sir  William  Thomson  being 
designated  as  one  of  the  mem- 
bers) to  test  the  motors,  and 
the  best  system  was  to  be 
adopted.  Several  meetings  were 
held,  but  the  scheme  finally  fell 
through.  This  agitation  acted 
as  a  stimulus,  however,  for 
shortly  afterward  the  Daft  Com- 
pany obtained  permission  to 


79 


80 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


equip  a  section  of  the  Ninth  Avenue  Elevated 
Railway  on  its  system,  while  the  Edison-Field 
interests  were  assigned  to  the  Second  Avenue 
road. 

From  that  time  until  August,  the  Daft  Com- 
pany was  busy  equipping  a  central    station, 


central  rail,  through  which  the  current  is  led  to 
the  motor,  is  elevated  above  the  outer  ones, 
resting  upon  the  insulator  shown  in  Fig.  70. 

The  central  station,  in  which  the  generating 
dynamos  are  placed,  is  situated  in  Fifteenth 
street,  a  distance  of  about  250  feet  west  of  the 


FIG.  83. — REAR  ELEVATION  OF  THE  "BENJAMIN  FRANKLIN." 


building  a  motor,  and  laying  down  the  central 
rail  required.  It  must  be  understood  that  the 
latter  operation  had  to  be  performed  during 
regular  traffic  hours,  with  trains  passing  every 
five  minutes  or  less. 

The  road  was  and  is  equipped  from  the  ele- 
vated railway  station  at  Fourteenth  street,  up 
to  Fifty-third  street,  a  distance  of  two  miles, 
in  which  a  heavy  grade  is  encountered.  The 


tracks,  and  connected  with  the  latter  by  a  stout 
conductor.  The  station  contains  a  Wright 
steam  engine  and  three  generators.  In  addi- 
tion there  is  a  small  dynamo  which  runs  the 
Daft  arc  lamps,  by  which  the  station  is  lighted 
at  night. 

The  motor  used  is  named  "  Benjamin  Frank- 
lin," with  which*  a  speed  of  twenty  miles  an 
hour  has  been  attained. 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


81 


The  illustrations,  Figs.  81,  82,  and  83,  show  the 
arrangements  of  the  motor  in  detail,  as  it  stood 
on  the  track,  the  cab  being  removed  for  the 
sake  of  clearness. 

In  the  arrangement  of  this  motor  Mr.  Daft 
has  entirely  avoided  the  use  of  belts,  power 
being  transmitted  by  friction  from  the  arma- 
ture to  the  drivers,  and  the  amount  of  it  can  be 
regulated  at  will  according  to  the  load.  As 
will  be  seen  from  the  plan,  Fig.  82,  the  motor- 
dynamo  is  supported  at  the  rear  on  a  shaft 
resting  in  bearings;  its  front  end  is  supported 
by  a  threaded  eye  through  which  passes  a  long 
screw,  which  is  turned  by  a  hand  wheel,  as 
shown  in  the  side-elevation,  Fig.  81.  The  arma- 
ture shaft  carries  a  friction  wheel  nine  inches 
in  diameter,  which  bears  upon  a  larger  friction 
wheel  three  feet  in  diameter,  keyed  to  the  axle 
of  the  main  drivers.  With  this  arrangement  it 
is  obvious  that  by  turning  the  large  screw  the 
upper  friction  wheel  can  be  pressed  against  the 
lower  to  any  desired  degree,  thus  preventing 
slip,  even  with  the  heaviest  loads.  By  means 
of  the  screw  also  the  entire  motor-dynamo  can 
be  raised  clear  above  the  driving  wheels,  so 
that  the  armature  can  be  taken  out  and  in- 
spected with  convenience. 

The  bronze  contact-wheel  which  bears  against 
the  central  rail  is  15  inches  in  diameter  and  is 
raised  and  locked  by  the  two  levers  at  the  side 
shown  in  the  view,  Fig.  81.  Another  lever  on 
the  other  side  constitutes  the  "reversing  lever," 
by  which  the  brushes  of  the  dynamo  are  set  so 
as  to  give  the  motor  a  forward  or  backward 
motion.  There  are  two  pairs  of  these  brushes 
and  the  motion  of  the  lever  alternately  puts 
either  pair  in  contact  with  the  commutator. 
Like  all  of  Mr.  Daft's  railway  motors,  this  one 
is  provided  with  his  electric  brakes.  These 
consist  of  large  electro-magnets  which,  being 
energized,  are  attracted  by  the  wheels  and 
press  against  them  like  the  ordinary  brake. 
The  motor-man  occupies  the  clear  space  in 
front  of  the  motor-dynamo,  and  before  him  is 
placed  the  case  containing  the  regulating, 
brake,  and  cut-off  switches,  as  shown  in  the  end 
view,  Fig.  83.  The  switch  at  the  right  controls 
the  brakes  and  that  to  the  left  makes  or  breaks 
the  current  as  desired.  In  the  centre  is  placed 
the  "regulator,"  by  which  the  speed  of  the 
motor  can  be  altered  at  will.  There  the  ter- 
minals of  the  compound  winding  of  the  motor- 
dynamo  are  brought,  and  by  moving  the  lever 
n 


to  the  different  notches,  the  resistance  of  the 
field  magnets  is  altered,  which  changes  the 
speed  correspondingly.  The  driving  wheels  are 
48  inches  in  diameter;  the  trailing  wheels  36 
inches.  Their  shafts  supporting  the  motor- 
dynamo  rest  in  specially  designed  resilient  bear- 
ings, so  as  to  reduce  any  shocks  to  a  minimum. 
The  motor  is  designed  for  75  horse  power  and  a 
normal  speed  of  eighteen  miles  per  hour,  with  a 
possible  speed  of  forty  miles.  The  motor  com- 
plete weighs  nine  tons,  and  measures  fourteen 
feet  six  inches  in  length,  over  all. 

With  the  "  Benjamin  Franklin  "  several  runs 
were  made,  to  the  satisfaction  of  all  apparently, 
except  Mr.  Daft  himself,  who  became  convinced 
that  the  motor  was  too  light  for  its  work,  i.  e., 
that  its  weight  was  not  sufficient  to  give  it  a 
grip  upon  the  track  adequate  to  the  load  it 
could  pull.  This,  however,  is  a  defect  in  the 
right  direction.  Mr.  Daft,  having  temporarily 
withdrawn  the  locomotive,  has  now  rebuilt  it, 
making  it  much  heavier,  and  the  demonstra- 
tion on  the  elevated  road  will  be  resumed  as 
this  volume  goes  through  the  press. 

A  recent  comer  in  the  field,  but  one  whose 
operations  are  destined  to  be  of  the  first  im- 
portance,isthe  Bentley-Knight  Electric  Railway 
Company,  owning  and  using  the  patents  of 
Messrs.  Edward  M.  Bentley  and  Walter  H. 
Knight,  whose  system  was  put  to  initial  experi- 
ment in  August,  1884,  on  the  tracks  of  the  East 
Cleveland  Horse  Railway  Company,  Cleveland, 
Ohio.  The  plant  consisted  as  usual  of  station- 
ary engines  and  dynamos  (Brush).  The  con- 
ductor was  placed  in  a  conduit  between  the  rails 
and  running  the  entire  length  of  the  road.  The 
current  was  taken  up  by  a  conductor  brush 
passing  through  a  slot  in  the  conduit  and  sliding 
in  contact  with  the  conductor  there — thus 
maintaining  unbroken  connection  with  the 
source  of  power.  The  road  equipped  in  this  ' 
way  was  two  miles  long,  with  a  branch  track, 
a  turnout  and  two  curves  of  45  feet  radius  ; 
and  a  railroad  crossed  it  at  an  angle  of  45°  on 
the  level.  Two  motors  were  employed.  The 
line  was  operated  experimentally  for  a  year, 
and  during  that  period  demonstrated  the  entire 
feasibility  of  electric  street  railways.  Our 
illustrations  Figs.  84  and  85  show  the  cars  as 
they  appeared  running  through  Cleveland.  In 
the  one  instance,  the  car  is  ploughing  its  way 
through  the  unusually  deep  snow  of  the  winter 
of  1S84-5.  At  no  time  was  the  snow  deep 


82 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


83 


enough  to  cause  any  interruption  of  traffic  so 
far  as  electricity  was  concerned.  In  the  other 
instance,  the  line  is  shown  under  normal 
summer  conditions. 

Since  that  time,  the  Bentley-Knight  Company, 
having  its  offices  in  New  York,  has  made 
arrangements  with  the  Rhode  Island  Locomo- 
tive Works  of  Providence,  R.  I.,  to  manufacture 
its  apparatus,  and  is  now  busily  engaged  mak- 
ing preparations  for  the  work  it  proposes  to 
undertake.  During  the  past  year  extraordinary 
popular  interest  has  been  manifested  in  every- 
thing pertaining  to  increased  rapid  transit 
facilities.  The  extension  of  the  New  York  and 
Brooklyn  elevated  lines,  the  proposed  introduc- 
tion of  the  same  system  throughout  our  greater 
cities,  and  the  preliminary  work  of  the  several 
sub-surface  railway  companies,  have  stimulated 
the  discussion  on  the  merits  of  such  systems  of 
motive  power  as  may  satisfactorily  accomplish 
the  work  of  the  steam  locomotive  without  the 
numerous  disadvantages  attendant  upon  its 
intramural  use. 

In  this  connection,  the  illustration,  Fig.  86, 
of  the  electric  locomotive  designed  by  the 
Rhode  Island  Locomotive  Works  cannot  fail 
to  be  of  interest.  This  illustration  is  taken 
from  the  working  drawings  of  the  Bentley- 
Knight  Company,  accompanying  various  esti- 
mates lately  submitted  by  its  engineers,  Messrs. 
Bentley  and  Knight. 

This  locomotive  is  especially  designed  for 
light  passenger  work.  It  is  standard  gauge,  has 
a  wheel-base  of  twelve  feet,  and  weighs  about 
4s,(i(X)  pounds,  all  of  which  weight  is  equally 
distributed  upon  its  six-coupled  sixty-eight 
inch  driving-wheels.  The  nominal  electrical 
capacity  of  its  twin  motors  is  500,000  watts. 
The  motor  armatures  are  thirty-six  inches  in 
diameter,  and  exert  their  force  upon  the  drivers 
without  the  intervention  of  any  of  the  various 
forms  of  gearing  which  some  think  have 
seriously  impeded  the  successful  introduction 
of  very  large  electric  railway  motors.  It  is 
equipped  with  electric  headlights,  bells,  and 
automatic  tubular  electro-magnetic  brakes, 
and  is  fitted  with  electric  connections  for  in- 
candescent lamps  and  brakes  throughout  the 
train.  It  has  no  reciprocating  parts,  and  is 
equally  adapted  for  use  with  overhead,  surface, 
or  sub-surface  connection  with  the  central 
power  station  of  the  line.  The  company's 
motors  are  built  so  as  to  be  exceedingly  power- 


ful, solid,  and  compact,  and  are  balanced  to  a 
nicety  ;  and  the  care  with  which  their  inter- 
changeable parts  are  manufactured  renders 
impossible  any  serious  interruption  of  work 
from  ordinary  accident. 

Some  noteworthy  plans  have  been  prepared 
by  the  New  York  District  Railway  with  a  view 
to  the  use  of  electric  locomotives,  of  the  kind 
just  described,  on  the  proposed  underground 
railway  for  Broadway,  New  York.  With  such 
a  road  Broadway  can  be  utilized  for  legitimate 
passenger  traffic.  It  has  long  suffered,  and 
until  recently  was  suffering,  from  the  diversion 
of  travel  to  streets  parallel  with  it.  The  slow 
and  clumsy  stages,  rattling  and  jolting  over  the 
rough  cobble  stones,  could  never  accommodate 
its  frequenters  satisfactorily.  Horse-car  lines 
with  which  the  thoroughfare  is  now  afflicted 
can  never  be  anything  but  an  impediment  to 
traffic;  while  they  are  much  too  slow  to  carry 
the  hundreds  of  thousands  of  persons  to  whom, 
in  modern  New  York,  rapid  transit  between 
the  Battery  and  the  Boulevards  has  become  an 
absolute  necessity.  But  while  horse-car  lines 
along  Broadway  are  a  disgrace  to  the  city,  the 
erection  of  an  elevated  railroad  would  be 
scarcely  short  of  sacrilege.  Broadway,  with 
its  natural  advantages,  ought  to  be  the  finest 
street  in  the  world.  But  that  it  cannot  be  if 
given  up  to  the  horse-car  or  to  the  abomination 
of  ugliness  called  an  "elevated road."  All  the 
requirements  of  rapid  transit  for  Broadway 
and  of  burying  the  wires  are  met  in  the  pro- 
posed "scientific  street."  Some  objections 
may  already  exist,  or  will  perhaps  arise  when 
the  work  of  carrying  out  the  scheme  is  actively 
prosecuted.  But  taken  in  its  entirety  the  idea 
is  one  that  recommends  itself  to  us  as  much  for 
.  its  practicability  as  for  its  brilliancy.  The 
underground  railway  would  give  additional 
value  to  property  all  over  Manhattan  Island, 
would  relieve  the  present  avenues  of  traffic 
that  are  now  so  sadly  crowded  morning  and 
night,  would  pay  handsomely  as  an  investment, 
and  would  preserve  Broadway  in  a  renovated 
condition,  picturesque  and  beautiful,  for  those 
grandiose  demonstrations  of  a  civil  and  military 
character  in  which,  as  a  people,  we  take  so 
much  pleasure.  Operated  by  electricity,  after 
the  manner  described,  the  underground  road 
would  be  very  pleasant  'for  travel.  Ventilated 
perfectly,  cool,  regular,  speedy,  without  noise 
or  dust  or  smoke,  it  would  compare  most  favor- 


84 


TUK    KLKCTIMC    MOTOR    AND    ITS   APPLICATIONS. 


i—i  -H-i-i—t—n *aJ >  — L  =-^_ — -  ^ ,r^r~ientf*_  _      • 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


89 


ably  with  any  other  kind  of  locomotion  on  the 
surface  or  on  elevated  tracks.  It  would  be  a 
road  worthy  of  Dr.  Richardson's  ideal  City  of 
Hygeia,  as  well  as  of  the  metropolis  of  the 
Western  Continent. 

The  main  features  of  the  road,  as  set  forth  in 
the  carefully  prepared  plans  of  the  company 
are  the  following : 

1.  Two  express  tracks,    throughout  the  line 
from  the  Battery  to  the  Harlem  river,  forming 
a    "through,"    standard  -  gauge,    rapid-transit 
road  of  enormous  capacity  and  capable  of  great 
speed,  witli  easy  access  and  egress  at  a  few 
commanding  points. 

2.  Two  "way"  tracks,  throughout  the  line 
from  the  Battery  to  the  Harlem  river,  forming 
a  rapid-traffic,    standard-gauge    line    between 
frequent  stations. 

:).  Continuous  galleries  on  either  side  of  the 
railways,  arranged  to  house  all  the  present 
water,  gas,  pneumatic,  steam,  and  other  pipes 
which  occupy  the  street  below,  together  with 
all  the  electric  cables  and  wires  now  arranged 
upon  poles  and  house-tops  above  the  streets, 
all  service-pipes  being  in  immediate  contact 
with  the  vault  wall  of  every  house  on  the  line, 
where  they  will  everywhere  and  at  all  times  be 
accessible  for  alteration,  repair,  replacement, 
and  inspection. 

4.  The  whole  to  be  built  and  operated  (as  to 
the  standard  section)  between  the  curb-lines 
and  (except  at  Canal  street)  above  mean  high- 
water,  for  the  purpose  of  avoiding  the  invasion 
of  the  valuable  vaults  of  Broadway,  and  for 
the  further  purpose  of  compensating  existing 
vested  corporation  rights,  without  encroaching 
upon  vested  private  rights,  or  private  property. 

The  roadway  of  lower  Broadway,  between 
the  curbs,  furnishes  all  the  accommodation  re- 
quired for  every  purpose.  It  is  divided  into 
two  sections;  the  one  centrally  placed  affords 
accommodation  for  the  way  and  express  trains; 
the  section  on  either  side  disposes  of  the  exist- 
ing impedimenta  of  the  street  at  the  point  of 
access  to  the  abutting  houses.  By  this  disposi- 
tion of  the  street  all  requirements  are  fulfilled. 
(1)  A  smooth,  noiseless,  and  unobstructed  sur- 
face is  provided  for  pedestrian  and  vehicular 
traffic,  (a)  Express  and  way  trains  for  through 
"  rapid  transit,"  and  for  rapid  transit  from  sta- 
tion to  station.  (3)  Permanent  housing  for 
sewer,  water,  gas,  steam,  pneumatic,  and  elec- 
tric conductors  and  pipes,  with  access  through- 


out for  inspection,  and  in  all  cases  in  immedi- 
ate contact  with  the  premises  where  the  con- 
nections are  to  be  made.  In  neither  express 
nor  way  stations  is  private  property  taken, 
nor  at  any  point  does  the  structure  abut  pri- 
vate premises,  even  during  construction. 

The  method  of  construction  is  as  follows: 
Street  excavation  is  effected  in  sections,  and  is 
governed  by  the  extent  and  character  of  the 
traffic,  travel  being  maintained  unobstructed  by 
a  system  of  movable  bridging.  A  uniform  plat- 
form of  concrete  a,  Fig.  88,  about  two  feet  in  thick- 
ness, floored  by  a  half  inch  of  Trinidad  asphalt, 
extending  across  the  street  at  a  maximum  base 
depth  of  about  seventeen  feet,  forms  a  founda- 
tion for  the  whole  structure.  Upon  this  is 
erected  the  external  vault  wall  b,  securing  to 
the  abutting  proprietor  the  permanent  use  of 
the  whole  vault  and  area  undisturbed  through- 
out the  standard  section.  This  vault  wall  is 
fitted  while  under  construction  with  suitable 
connections  for  gas,  steam,  electricity,  sewer, 
and  water  at  every  house.  This  wall  is  also 
the  external  wall  of  the  pipe  galleries  c,  ar- 
ranged adjacent  to  both  curbs.  The  galleries 
are  subdivided  longitudinally  and  continuously 
by  beams  riveted  to  their  internal  and  inserted 
in  their  external  walls,  which  support  the  sew- 
ers and  other  pipes.  Access  throughout  is  pro- 
vided at  the  termini  and  stations,  and  they  are 
calculated  for  access  to,  housing,  and  inspec- 
tion of,  the  tubes,  pipes,  and  wires.  The  elec- 
trical conductors  d,  of  the  various  telegraph, 
telephone,  lighting,  burglar-alarm,  messenger, 
and  time  companies  are  arranged  anti-induct- 
ively,  upon  shelves  riveted  to  the  roof  and  upper 
gallery  beams.  There  being  no  permanent 
floor  above  the  foundation,  the  pipes  in  either 
gallery  are  accessible  from  above  or  below. 
Street  opening  for  repair,  replacement,  or  con- 
nection is  thus  wholly  obviated.  The  internal 
wall  supporting  the  galleries  is  formed  by  iron 
columns  e,  placed  four  feet  apart,  and  coinci- 
dent with  those  forming  the  outer  wall  of  the 
"  way  "  railways.  These  columns  are  composed 
of  two  angle  irons  riveted,  and  rest  upon  a  con- 
tinuous granite  foundation  /.  The  galleries 
contribute  largely  to  the  cost  of  construction, 
but  are  indispensable  to  a  safe,  convenient, 
and  equitable  replacement  of  present  impedi- 
menta enjoying  vested  rights,  and  to  access 
thereto  at  every  house  on  the  route.  The  space 
remaining  between  the  pipe  galleries  is  dis- 


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MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


93 


posed  in  four  railways,  for  the  accommodation 
of  an  up-way  and  express  and  a  down- way  and 
express  train  g.  These  ways  are  formed  by 
five  rows  of  columns,  each  composed  of  four 
angle  irons,  arranged  longitudinally  four  feet 
apart,  resting  on  a  continuous  granite  base,  the 
spaces  between  the  columns  at  the  foundation 
and  the  roof  being  filled  by  a  panel  composed 
of  a  tough,  non-resonant  material,  "fcrflax" 
//,  composed  of  steel  wire,  vegetable  fibre,  and 
solidified  oil  compressed  into  a  solid  panel  by 


the  permanent  street,  upon  which  the  pave- 
ment will  be  relaid.  This  structure  as  a  whole 
contemplates  the  minimum  of  excavation,  the 
maximum  of  capacity,  the  greatest  number 
and  most  equal  distribution  of  points  of  sup- 
port, and  consequent  maximum  of  strength 
and  stiffness  in  use. 

The  railways  form  open  cylinders  from  sta- 
tion to  station,  and  the  trains  being  of  approxi- 
mate cross-section  constitute  loose  pistons 
always  moving  in  the  same  direction;  the  ob- 


FIG.  90. — VAN  DETOELE  GENERATOR. 


hydraulic  power.  This  panel  fulfils  a  double 
function:  it  completes  the  enclosure  for  pur- 
poses of  ventilation,  and  it  prevents  resonance, 
which  might  be  caused  by  the  rapid  passage  of 
a  train  through  an  enclosure  with  metallic 
walls.  The  roof  is  supported  and  the  whole 
structure  tied  by  beams  i  placed  four  feet 
from  centres  which  extend  across  the  entire 
span,  bolted  at  every  eight  feet  to  the  columns, 
the  ends  being  inserted  in  the  vault  wall. 
Upon  these  beams  the  steel  ten-inch*  span, 
buckle-plate  roof  k  is  laid  and  bolted;  over 
this  is  a  two-inch  skin  of  Trinidad  asphalt,  as 
a  protector  from  chemical  contact  and  damp- 
ness and  as  a  slight  cushion.  Above  this  is 
placed  six  inches  of  concrete,  which  completes 
12 


vious  effect  is  the  establishment  of  a  ventilating 
current,  dependent  for  its  force  upon  the  ap- 
proximation of  cross-sections,  the  speed  of  the 
trains,  and  the  integrity  of  the  tunnels;  as  the 
products  of  artificial  combustion  are  excluded 
from  the  tunnels,  the  requirements  of  ventila- 
tion are  reduced  to  a  minimum,  and  perfectly 
performed.  The  traffic-rails,  the  electrical  con- 
ductor conduit  I,  and  the  guard  -  plate  are 
bolted  to  the  same  steel  tie,  which  arrange- 
ment secures  perfect  alignment,  the  tie  being 
permanently  set  in  the  concrete  foundation. 
A  deflecting-plate  m  attached  to  the  structure 
at  the  cornice  line  and  the  guard-plate  external 
to  the  rail  render  destructive  derailment  im- 
possible. 


94 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


Roads  and  galleries  constructed  in  this  way 
have  the  incidental  advantage  of  being  access- 
ible from  one  to  another  at  any  point  and 
across  the  whole  system,  from  curb  to  curb, 
performing  the  vital  functions  of  ventilation, 
and  of  guaranteeing  complete  immunity  from 
collision  or  derailment,  without  obstructing 
transverse  communication  when  it  is  required. 

This  plan  was  first  brought  to  the  attention 
of  electricians  in  1884,  when  Col.  Rowland  R. 
Hazard  presented  a  paper  on  the  subject  at  a 
meeting  of  the  American  Institute  of  Electrical 


FIG.  91. — LARGE  VAN  DEPOF.LF.  MOT  OH. 

Engineers;  and  it  is  now  familiar  to  the  public. 
Fig.  87  shows  a  standard  section  of  the  line  on 
the  Broadway  division.  Fig.  88  is  a  view  of 
the  road  at  the  proposed  station  near  Fourteenth 
street  and  Union  Square.  Fig.  89  gives  an 
illustration  of  the  method  of  making  connec- 
tions in  the  pipe  and  wire  galleries  for  mains 
and  way  service  of  every  description. 

The  Arcade  Railway  Company,  also  pro- 
posing to  construct  an  underground  railway 
along  Broadway,  announces,  too,  its  intention 
to  use  electricity  for  locomotive  purposes. 
The  work,  whenever  carried  out,  and  by  whom- 
soever, will  be  one  of  great  profit,  utility,  and 
convenience. 


The  Van  Depoele  electric  railway  system, 
now  in  successful  operation  at  so  many  places 
in  this  country,  as  well  as  in  Canada,  is  the 
invention  of  Mr.  Charles  J.  Van  Depoele,  the  elec- 
trician of  the  Van  Depoele  Electric  Manufactur- 
ing Company,  of  Chicago,  Illinois,  and  it  is  the 
result  of  constant  experiment  in  generators,  mo- 
tors, and  the  transmission  of  power,  beginning 
in  1874  and  running  down  to  the  present  time. 

The   generator,  Fig.  90,  is   a   model  of  sim- 
plicity.    The  motor  is   changed  slightly  from 
the  ordinary  Van   Depoele  dynamo   to  adapt 
it  to  the   work  of  transmission  of  power. 
These  machines  are  of   various  sizes  and 
styles,  from  a  motor  weighing  one   pound 
to  the  eighty  horse-power  motor  weighing 
eight   thousand  pounds.     The  accompany- 
ing cut,  Fig.  91,  illustrates  the  large  motor 
for  running  railway  trains. 

The  first  railway  operated  under  the  Van 
Depoele  system  was  laid  in  Chicago  in  the 
winter  of  1882-3,  and  the  current  was  con- 
veyed by  a  wire.  In  the  fall  of  the  same 
year  a  car  was  run  at  the  Industrial  Expo- 
sition in  Chicago  from  an  overhead  wire. 

In  1884  a  train  was  run  at  Toronto,  On- 
tario, by  the  Van  Depoele  system,  using 
an  underground  conduit.  This  road  was 
operated  successfully  and  carried  the  pas- 
sengers from  the  street  car  line  to  the  ex- 
position grounds,  and  was  a  perfect  success. 
It  was  operated  as  long  as  the  exposition 
lasted.  This  train  averaged  200  passengers 
per  trip  ;  the  speed  was  about  thirty  miles 
per  hour. 

In  the  fall  of  1885,  at  Toronto,  the  road 
connecting  the  exposition  grounds  with  the 
street  railway,  a  distance  of  one  mile,  was 
equipped  with  a  Van  Depoele  motor.  Fig.  92. 
This  train  consisted  of  three  cars  and  a  motor- 
car. As  there  was  only  one  track,  it  was  neces- 
sary to  run  at  a  high  rate  of  speed.  An  over- 
head wire  was  used  as  a  conductor,  it  requiring 
but  a  few  days  to  put  it  in  operation  ;  an  or- 
dinary forty-light  dynamo  was  used,  driven  by 
a  Doty  10  x  10  engine. 

The  average  speed  of  the  train  was  about  thirty 
miles  per  hour.  The  trains  carried  from  225  to 
250  people,  and  the  average  number  of  pas- 
sengers per  day  was  over  10.000.  The  amount 
of  coal  consumed  was  1,000  pounds  per  day. 
This  road  carried  all  the  passengers  that  could 
be  gotten  on  and  off  the  cars. 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA.  95 


ni.  il'2. — VAX  DKI'OKI.K  KI.KCTKIC  RAILWAY,  Touoxro,  CAN. 


FIG.  93. — MIXXKAI-OLIS  RAILWAY — VAX  DEPOKLK  SY.-U:M. 


THE  ELECTRIC   MOTOR  AND   ITS   APPLICATIONS. 


FIG.  'Jl. — Ki.Kuriuc  STKEET  RAILWAY,  MONTGOMERY,  ALA. — VAN  DEI-UEI.E  SYSTEM. 


FIG.  95.— ELECTUIC  STREET  RAILWAY,  MONTGOMERY,  ALA.— VAN  DUOKU  SYSTEM. 


MODERN  ELECTRIC  RAILWAY  AND  STREET  CAR  LINE  IN  AMERICA. 


97 


For  the  purpose  of  conducting  experiments,  a 
portion  of  the  South  Bend  Railway  line  was 
equipped  in  the  fall  of  1885  and  several  inde- 
pendent cars  were  run  with  small  motors,  the 
generator  being  driven  by  water-power.  It  was 
a  distinct  success,  the  cars  travelling  in  different 


quite  a  distance  from  the  track,  and  is  driven 
by  an  old  slide-valve  engine,  12  X  18  cylinder, 
making  125  revolutions  per  minute.  The  con- 
sumption of  coal  is  about  3,000  pounds  for 
seventeen  hours'  run.  Forty-eight  trains  are 
run  each  way  daily,  running  from  0  A.  M.  to 


Fit;.  !)6. — I'KXDLETON  METHOD  OF  ATTACHING  MOTORS  TO  CARS. 


directions  from  the  same  conductor.  This  road 
has  not  yet  been  equipped,  however,  owing  to 
change  in  management. 

At  New  Orleans,  during  the  late  exposition,  a 
train,  consisting  of  three  large  cars,  was  run 
successfully  until  the  end  of  the  exposition. 

The  Minneapolis,  Lyndale  &  Minnetonka 
Railway  Company,  of  Minneapolis,  have  been 
obliged  to  discontinue  the  running  of  their  loco- 


11.30  P.  M.  Trains  are  composed  of  from  three 
to  four  closed  railway  coaches  weighing  eleven 
tons  each,  or  of  a  larger  number  of  open  cars 
weighing  six  tons  each.  As  many  as  eight  of 
these  cars  have  been  hauled  at  one  time,  and 
this  up  a  grade  of  three  and  one-half  per  cent., 
and  the  cars  crowded  to  their  utmost  capacity 
with  passengers,  giving  a  total  of  ninety-one 
tons.  The  motor  works  perfectly. 


FIG.  07. — PE.NDLKTOX  METHOD  OF  ATTACHING  MOTORS  TO  CARS. 


motives  in  the  more  thickly  settled  portions  of 
the  city  of  Minneapolis,  and  an  arrangement 
was  made  to  bring  the  cars  into  the  city  and 
deliver  them  back  to  the  steam  locomotives. 
This  is  being  done  successfully  (Fig.  93).  The 
motor  is  located  upon  a  cheaply  constructed 
motor-car  and  takes  the  current  from  an  over- 
head copper  wire.  The  generator  is  placed 


At  Montgomery,  Ala.,  the  Capital  City  Street 
Railway  have  been  running  two  cars  for  some 
time  (Figs.  94  and  95).  The  grades  are  over 
seven  per  cent.;  the  distance  is  over  one  and 
one-half  miles.  Motors  are  placed  on  the  plat- 
form of  each  car  and  do  the  work  well.  The 
speed  over  the  grade  is  six  miles  per  hour.  The 
cars  run  sixteen  hours  per  day, and  the  generator 


THE   ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


is  driven  by  an  old-fashioned  slide-valve  engine 
stationed  250  feet  from  the  boiler.  The  amount 
of  coal  consumed  per  day  is  3,000  pounds,  in- 
cluding getting  up  steam  from  cold  water. 

At  Windsor,  Ontario,  a  train  has  been  run- 
ning on  the  track  of  the  Windsor  Electric  Street 
Railway  Company  since  June  G,  and  giving 
good  satisfaction.  The  distance  travelled  is 
about  two  miles.  Roads  equipped  with  the 
Van  Depoele  system  have  recently  gone  into 
operation  at  Detroit,  Mich.,  Appleton,  Wis., 
and  Scranton,  Pa. 

Acting  upon  the  idea  that  the  development 
of  the  electric  propulsion  of  street  cars  might 
be  greatly  advanced  by  a  device  to  allow  of  a 
ready  and  cheap  method  of  attaching  the  motors 
to  the  existing  cars,  Mr.  John  M.  Pendleton,  of 
New  York,  has  designed  an  ingenious  plan  of 
attachment  for  this  purpose,  which  we  illus- 
trate in  the  accompanying  engravings.  Figs. 
90  and  97.  These  show  respectively  a  front 
and  side  elevation  of  a  car  equipped  with  the 
motor,  according  to  Mr.  Pendleton's  plan.  The 
general  arrangement  of  wheels  and  axles,  it 
will  be  observed,  is  the  same  as  that  of  the 
ordinary  horse  car. 

The  electric  motor  is  suspended  from  the  floor 
of  the  car,  and  the  revolving  armature  carries 
a  coiled  spring  extension  at  each  end,  terminat- 
ing in  a  worm  or  screw-pinion  wheel,  held  by 
journals  on  each  side. 

The  interposition  of  the  spring  presents 
several  advantages,  for  it  not  only  allows  for 
the  distortion  of  the  car  with  varying  loads,  or 


from  other  causes,  tending  to  throw  the  axis  of 
the  motor  out  of  line,  but  in  addition  the  springs 
relieve  the  axles  of  any  sudden  strain  due  to 
rapid  starting  or  stopping  of  the  motor.  The 
retaining  links  beside  the  springs  allow  of 
torsion,  but  limit  the  extension  and  contraction 
of  the  shaft  where  heavy  strains  occur,  such  as 
on  the  ascent  of  heavy  grades. 

It  will  be  noted  that  the  two  axles  are  dif- 
ferently geared,  one  having  the  worm  pinion 
on  the  top,  and  the  other  at  the  bottom,  of  the 
worm  wheels,  respectively.  By  this  arrange- 
ment the  thrust  on  the  motor  is  equalized  and 
friction  on  the  collars  is  avoided. 

The  worms  are  cut  witli  a  coarse  pitch  so  as 
to  allow  free  movement  of  the  car  ;  but  the 
speed  is  reduced  by  the  worm  wheels  attached 
to  the  axles,  in  the  ratio  of  12  to  1,  enabling  the 
motor  to  operate  at  the  rate  of  1,000  revolu- 
tions, corresponding  to  a  speed  of  eight  miles 
per  hour  for  the  car. 

With  the  idea  of  adapting  the  system  to  ex- 
isting rolling  stock,  the  worm  wheels  are  split 
and  securely  bolted  to  the  axles  and  keyed  in 
addition.  The  hub  of  the  split  worm-wheel 
carries  a  cover  or  box,  which  is  made  oil-tight 
and  which  surrounds  the  worms.  These  boxes 
are  filled  with  oil,  which  insures  a  constant 
and  copious  lubrication,  reducing  the  friction 
and  wear  to  a  minimum,  and  preventing  the 
access  of  dust  to  the  working  parts. 

(In  a  later  chapter  will  be  found  illustrated 
descriptions  of  the  Sprague,  Henry,  and  other 
systems.) 


CHAPTER  VII. 


T  HE    USE   OR    STORAGE    BATTERIES   WITH    ELECTRIC    MOTORS 

FOR   STREET    RAILWAYS. 


IN  the  present  chapter  we  take  up  a  method 
which,  although  now  looked  upon  with  distrust 
by  many,  rnay  yet  prove  to  be  one  of  the  most 
feasible  means  for  the  propulsion  of  railway 
cars.  We  refer  to  the  employment  of  accumu- 
lators, the  stored  energy  of  which,  conveyed  to 
a  motor  in  the  form  of  current,  sets  it  in  motion, 
and  with  it  the  car.  While  this  mode  of  pro- 
pulsion was  until  lately  in  the  experimental 
state,  the  progress  made  has  been  such  that  a 
satisfactory  solution  of  the  problem  appears  to 
have  been  reached;  indeed,  the  immediate 
future  will  see  cars  propelled  by  the  energy  de- 
rived from  accumulators,  with  success,  judged 
from  the  standpoint  both  of  convenience  and 
economy. 

If  we  undertake  to  examine  into  the  merits 
and  demerits  of  such  a  system,  it  is  discovered 
that  the  main  argument  brought  forward 
against  the  use  of  accumulators  for  this  purpose 
consists  in  a  demonstration  of  the  large  loss  of 
power  which  a  number  of  transformations 
entail.  That  a  number  of  reducing  stages  have 
to  be  gone  through,  is  obvious,  for  we  have: 
I.  The  mechanical  energy  developed  by  the  en- 
gine. II.  The  conversion  of  mechanical  into 
electrical  energy  in  the  dynamo.  III.  The 
conversion  of  electrical  into  chemical  energy 
in  the  accumulator.  IV.  The  reconversion  of 
chemical  into  electrical  energy.  V.  The  final 
transformation  of  electrical  into  mechanical 
work  by  the  motor.  Here,  it  will  be  seen,  four 
transformations  take  place  which  must  neces- 
sarily result  in  loss,  but  it  is  boldly  asserted 
that  by  good  apparatus  and  economical  man- 
agement these  losses  are  reduced  to  a  point 
below  that  experienced  with  other  systems, 
and  with  the  gain  of  many  offsetting  advan- 
tages. 

There  are  two  principal  methods  in  competi- 
tion with  electricity  to  supplant  the  use  of 
norses  on  tram  lines,  and  they  are  steam  and 


compressed  air.  In  comparing  electricity  with 
steam,  we  find  two  ways  in  which  the  latter 
can  be  applied,  viz.,  by  steam  locomotives  di- 
rect, and  by  an  endless  cable  driven  by  a  steam 
engine.  Using  locomotives,  there  is  required  a 
separate  engine  and  boiler  for  each  car  or  train 
of  cars,  and  a  consumption  of  fuel  between  six 
and  seven  pounds  of  coal  per  horse  power  per 
hour,  which  latter  figure  may  be  considerably 
exceeded  where  frequent  stoppages  occur;  and 
to  this  must  be  added  the  other  expenses  inci- 
dental to  engine-running.  With  cable  trans- 
mission, there  need  be  only  one  large  engine 
using  two  and  one-half  pounds  of  coal  per 
horse  power  per  hour;  but  the  cost  of  construc- 
tion of  a  tunnel  for  the  passage  of  the  cable 
and  of  intricate  machinery  for  grades  and 
curves  is  a  large  item  which  must  be  taken 
into  consideration.  With  compressed  air,  the 
use  of  separate  locomotives  is  necessary,  and 
while  the  engine  may  not  use  more  coal  than 
in  the  preceding  case,  the  large  loss  of  power 
due  to  the  wasted  heat  of  compression  makes 
it  a  matter  of  doubt  whether  this  system  can 
be  economically  employed  for  the  purpose, 
often  as  it  has  been  attempted.  Taking  up  (un- 
original system,  all  that  would  be  required  is  a 
good  central  engine  as  in  the  preceding  exam- 
ples, and  a  dynamo,  while  each  car  would  be 
supplied  with  a  small  electro-motor  and  storage 
batteries  fitted  into  compartments  in  the  car. 
Objections  have  also  been  raised  with  respect 
to  the  power  lost  in  transporting  the  'dead 
weight  of  the  accumulators  and  motor,  but 
even  this  objection  appears  to  have  been 
greatly  lessened,  so  that,  as  compared  with 
steam  and  compressed-air  locomotives,  the  for- 
mer shows  up  quite  favorably. 

These  are  the  conditions,  roughly  sketched, 
that  enter  into  the  problem,  the  solution  of 
which  lies  in  the  choice  between  a  system  re- 
quiring a  large  original  outlay  of  capital  and 


100 


THE   ELECTRIC   MOTOE  AND   ITS  APPLICATIONS. 


one  in  which  the  cost  of  power  or  running  ex- 
pense is  the  principal  item. 

Looked  at  from  the  standpoint  of  convenience 
and  applicability,  the  propulsion  of  tram-cars 
through  the  medium  of  accumulators  must  be 
conceded  to  be  second  to  no  other.  The  batter- 
ies occupy  no  valuable  space,  being  stowed 
under  the  seats,  while  the  motor  can  be  placed 
under  the  car  body  as  shown  in  our  illustra- 


FIG.  98. — LOCOMOTIVE   DRIVEN   BY   ACCUMULATORS, 
LISIEUX,  FRANCE. 

tions.  Adding  to  this  the  absence  of  smoke, 
dust,  escaping  steam  and  its  accompanying 
noise,  it  becomes  manifest  that  the  points  in 
favor  of  such  a  system  are  of  a  most  decided 
nature. 

While  it  is  hardly  probable  that  the  storage 
battery  will  supplant  the  locomotive  for  heavy 
and  continuous  railway  traffic,  it  is  evident 
that  such  a  service  is  eminently  applicable  on 
street  car  lines  within  city  limits;  and  from 
this  standpoint  we  have  viewed  it  here.  We 
now  pass  on  to  examine  what  has  been  done 
towards  putting  the  system  in  a  practical  shape. 


One  of  the  instances  in  which  it  has  been 
applied  successfully  is  presented  by  the  ar- 
rangement in  use  at  a  bleaching  establishment 
at  Breuil-en-Auge,  near  Lisieux,  France.  Fig. 
98  shows  a  locomotive,  the  accumulators  being 
carried  on  a  tender  which  is  not  shown.  The 
installation  is  used  for  the  purpose  of  gathering 
and  folding  the  sheets  of  linen  which  are  spread 
out  upon  a  meadow  to  bleach.  The  peculiar 
nature  of  the  case  made  the- use  of  accumula 
tors  the  only  method  which  could  be  applied.  A 
steam  engine  was  out  of  the  question,  since  the 
dust  and  smoke  would  injure  the  linen,  while 
to  lead  the  wires  through  the  tracks  laid  on  a 
damp  meadow  might  have  entailed  a  large  loss 
of  current. 

London,  Brussels,  and  Paris  have  all  seen 
tram-cars  run  by  storage  batteries  in  operation, 
and  Fig.  O'J  represents  a  car  which  for  some 
time  ran  in  Paris.  The  illustration  will  give  a 
good  idea  of  the  manner  of  disposal  of  the  ac- 
cumulators and  motor. 

Early  in  1883  a  similar  experiment  in  street 
car  locomotion  by  storage  was  made  at  Kew 
Bridge,  London,  on  the  Acton  tramway  line. 
The  car  used  at  the  Kew  Bridge  experiment 
and  shown  in  the  accompanying  illustration, 
Fig.  100,  was  fitted  with  an  accumulator  battery 
consisting  of  fifty  Faure-Sellon-Volckmar  cells, 
each  measuring  13  in.  by  11  in.  by  7  in.,  and 
weighing  about  eighty  pounds.  The  accumu- 
lator battery  was  capable  of  working  a  tram-car 
with  its  full  load  for  half  a  day,  or  in  other 
words  seven  hours.  When  charged  it  contained 
about  500  ampere-hours,  of  which  400  were  with- 
drawn with  the  greatest  regard  to  economy. 
Tire  accumulators  were  stored  under  the  seats 
of  the  car,  and  the  current  was  conveyed  by 
insulated  wire  to  a  Siemens  dynamo  machine 
acting  as  a  motor,  and  connected  with  the  axle 
of  the  wheel.  As  soon  as  the  communication 
between  the  boxes  and  the  machine  was 
effected,  the  electric  current  being  led  into  the 
motor  set  the  armature  in  revolution,  and  the 
power  was  conveyed  to  a  pulley  fastened  on 
the  same  axle  as  the  armature.  The  Siemens 
machine  worked  most  favorably  with  an 
electromotive  force  of  100  volts  and  a  current 
of  sixty  amperes,  and  as  746  watts  constitute 
an  electrical  horse  power,  the  result  was  a  con- 
sumption of  eight  electrical  horse  power  and  a 
yield  on  the  pulley  of  five  and  three-fifths  me- 
chanical horse  power.  The  action  of  the  motor 


USE  OF  STORAGE  BATTERIES  WITH  ELECTRIC   MOTORS. 


101 


could  be  reversed  at  will,  and  the  power  in- 
creased or  diminished  as  required  by  adding  to 
or  taking  from  the  number  of  cells  composing 
the  accumulator  by  means  of  a  simple  switch; 
while  by  breaking  the  circuit  the  motive  power 
was  stopped,  and  the  brake  being  then  applied 
the  car  was  almost  -immediately  brought  to  a 
stand-still. 

At  the  trial  trip  several  noted  electricians 
vvere    present,   and  the  experiment    was  pro- 


tery  and  electric  motor  at  the  close,  qf'ltfsi, 'and' 
made  a  tramway  four  hundred  yardsvlojng  fo? 
the  car  to  run  upon.  The  experimental  trials 
with  it  were  carried  on  for  many  months,  and 
the  results  were  extremely  satisfactory.  The 
whole  series  of  accumulators  in  the  car  weighed 
only  one  and  one-quarter  tons,  and  the  motor, 
gearing,  and  accessories  weighed  about  half  a 
ton,  bringing  the  total  weight  of  the  motive 
power  to  one  and  three-quarter  tons.  The  car, 


FIG.  99.— CAR  USED  WITH  ACCUMULATORS,  PARIS. 


nounced  by  them  fairly  satisfactory.  The  car 
could  carry  a  load  of  forty-six  persons,  the  total 
weight  being  about  five  tons.  The  speed  attained 
was  six  miles  per  hour,  and  the  car  ran  smoothly 
along  level  road  and  down  hill.  The  cost  of 
running  the  car  in  this  manner  was  estimated 
at  a  sum  equivalent  to  $1.50  per  day  for  each 
car,  against  $6.25  for  horses.  The  car  was 
lighted  by  Swan  incandescent  lamps,  and  fur- 
nished with  electric  bells,  all  worked  from  the 
same  accumulators. 

Under  the  direction  of  their  engineer,  Mr. 
Reckenzaun,  the  Electrical  Power  and  Storage 
Company,  London,  fitted  up  a  car  with  bat- 

13 


which  had  been  transformed  out  of  an  old  one, 
for  many  years  running  on  the  Greenwich  and 
Westminster  line,  weighed  two  and  one-half 
tons — the  modern  cars  on  the  American  lines 
weigh  only  thirty-two  cwt. — and  its  load  of 
forty-six  passengers  brought  the  total  up  to  five 
and  one-half  tons.  Comparing  the  weight  of  this 
motive  power  with  steam  or  compressed-air  loco- 
motives, which  do  not  weigh  less  than  from 
eight  to  ten  tons,  the  comparison  speaks  well 
for  electricity.  The  car,  moreover,  was  put  on 
two  bogies,  each  with  four  wheels,  whereby  the 
wheel  base  was  diminished,  and  the  cars  could 
turn  corners  and  encounter  curves  of  very  short 


• 


X 
K 


c 

h— 

pi 


H 


USE  OF  STORAGE   BATTERIES  WITH  ELECTRIC  MOTORS. 


103 


radius.  Another  advantage  of  this  arrange- 
ment was,  that  there  was  no  such  overhanging, 
and,  consequently,  no  such  rocking  in  travel- 
ling, as  there  is  in  the  ordinary  cars  which  have 
their  four  wheels  placed  at  short  distances  from 
the  centre. 


on  ordinary  street  car  lines.  The  car  at  Mill- 
wall  could  be  run  for  two  hours  with  one  charg- 
ing of  the  accumulators,  starting,  stopping, 
and  reversing  every  minute.  The  used  ac- 
cumulators were  taken  out  and  the  car  supplied 
with  fresh  charged  cells  in  as  short  a  time  as  is 


|E£ 


FIG.  101.  —  ItKcKKx/Afx  CAR — ELEVATION. 


The  next  experimental  line,  at  Millwall,  was  a 
difficult  one.  The  line  made  a  bend  of  nearly  a 
right  angle,  and  an  actual  curve  of  thirty-three 
feet  radius  had  to  be  passed.  The  inclines  varied 
from  a  level  on  the  portion  from  the  shed-end 
to  the  curve,  and  rose  thence  from  one  in  forty  to 
a  gradient  of  one  in  seventeen  at  the  opposite 
termination.  This  steep  incline  had,  conse- 
quently, to  be  faced  without  a  run,  a  rush  being 
prevented  by  the  sharp  curve  intervening.  The 


occupied  by  the  changing  of  horses.  This  opera- 
tion was  accomplished  with  ease  by  means  of  a 
trolley  fitted  with  rollers.  The  accumulators 
were  placed  under  the  seats  completely  out  of 
sight ;  the  motor  was  placed  under  the  car  very 
neatly,  and  was  only  seen  when  looked  for. 
The  interior  was  furnished  with  four  20-candle 
power  incandescent  lights,  and  with  pushes  for 
electric  bells  for  communication  between  the 
passengers  and  the  conductor.  The  travelling 


FIG.  102.— RKCKKNZAUN  CAR— PLAN. 


new  car  overcame  all  these  difficulties  and  made 
its  way  with  surprising  speed  and  steadiness. 
It  has  been  considered  very  adverse  to  the  eco- 
nomical use  of  stored  electricity  that  so  many 
transformations  of  energy  had  to  be  encountered, 
but  the  practical  experience  of  the  Millwall  ex- 
periments was  asserted  to  be  that  the  running 
expenses,"including  fifteen  per  cent,  for  depre- 
ciation of  machinery,  and  fifty  per  cent,  on  ac- 
cumulators, were  about  half  the  cost  of  horses 


was  perfectly  free  from  vibration  or  tremor  of 
any  kind,  and  was  absolutely  faultless  in  that 
respect.  Every  detail,  mechanical  or  electrical, 
had  been  well  thought  of  and  well  worked  out. 
Within  the  last  few  months,  Mr.  Reckenzaun 
has  made  again  a  highly  successful  demonstra- 
tion— this  time  at  Berlin — with  his  motor  ap- 
plied to  street  cars  and  deriving  current  from 
storage  batteries.  Our  illustrations,  Figs.  101 
and  102,  show  the  car,  in  part  sectional  elevation 


104 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


and  in  plan,  and  give  the  general  arrangements 
which  have  been  worked  out  with  great  care 
and  do  credit  to  Mr.  Reckenzaun's  perseverance 
and  skill.  The  various  arrangements  may  be 
classed  under  the  following  headings,  viz.:  1. 
The  battery.  2.  The  motors.  3.  Reversing  and 
transmitting  gear.  4.  Speed  regulation.  5. 
The  brakes. 

1.  The  battery  consists  of  sixty   cells,  each 
weighing  forty  pounds  and  with  a  capacity  of 
150  ampere-hours.     They  are  placed  on  a  board 
under  the  seats  of  the  car,  resting  on  rollers,  so 
that  they  can  be  readily  run  in  and  out.     There 
are  two  rows  of  fifteen  cells  each  under  each  seat. 
They  are  coupled  in  series,  and  hence  give  an 
electromotive  force  of  from  110  to  120  volts. 

The  storage  batteries  are  changed  every  two 
or  four  hours,  according  to  the  length  of  the  trip, 
and  the  change  can  be  performed  in  about  three 
minutes,  not  occupying  more  time  than  a 
change  of  horses. 

2.  The  electric  motors  employed  are  of  the 
Reckenzaun  model.     They  weigh  420  pounds, 
and  are  capable  of  delivering  from  four  to  nine 
horse  power.     At  120  volts  their  efficiency  is 
seventy -five  per  cent.,  and  at  the  nominal  speed 
of  seven  miles  per  hour  they  make  1,000  revolu- 
tions per  minute.     But  this  speed  can  be  raised 
to  ten  miles  per  hour. 

3.  The  reversing  arrangement  by  which  the 
car  is  run  in  either  direction  consists,  as   in 
many  electric  railways,  of  two  pairs  of  brushes, 
either  one  of  which  is  brought  in  contact  with 
the  commutator,  according  to   the  desired  di- 
rection.    For  this  manipulation  of  the  brushes 
a  lever  similar  to  the  reversing  lever  of  a  loco- 
motive is  employed. 

The  car  body,  as  will  be  seen,  is  mounted 
upon  two  trucks,  each  of  which  carries  a  motor; 
and  worm  gearing  is  employed  to  transmit 
power  from  the  armature  shaft  to  the  axles 
of  the  wheels.  Objections  have  been  raised 
against  this  form  of  gearing,  on  account  of  the 
high  friction  encountered,  but  Mr.  Reckenzaun's 
experiments  show  that  only  fifteen  per  cent, 
is  lost  in  transmission.  He  has  also  demon- 
strated, contrary  to  the  general  opinion,  that 
the  car  runs  freely  on  a  down  grade,  its  prog- 
ress not  being  impeded  by  the  worm  and  worm 
wheel.  It  was,  of  course,  necessary  to  select 
a  particular  pitch  of  the  screw  worm  to  make . 
this  possible,  and  also  to  insure  excellent 
lubrication. 


4.  Changes  in  speed  are  effected  by  different 
combinations  between  the  whole  battery  and 
the  two  motors.  In  the  electrical  car  tested  at 
the  Antwerp  Exhibition,  and  of  which  an  in- 
teresting account  will  be  found  a  few  pages 
later,  the  same  thing  was  accomplished  by  a 
change  of  potential,  effected  by  cutting  out  a 
corresponding  number  of  batteries.  This,  of 
course,  prevents  the  batteries  from  being  dis- 
charged uniformly,  arid  is  not  conducive  to  their 
long  life.  Mr.  Reckenzaun's  method  of  employ- 
ing all  the  batteries  during  all  speeds  evidently 
overcomes  this  objection  and  allows  of  three 
combinations,  viz.:  All  cells  connected  with 
one  motor  ;  all  the  cells  connected  with  the  two 
motors  joined  in  series,  or  all  cells  connected 
with  both  motors  joined  in  parallel  circuit. 
These  three  methods  of  coupling  suffice  to  give 
the  car  a  speed  corresponding  to  the  walk,  the 
trot,  and  the  sharp  trot  of  a  horse.  The  switch 
which  accomplishes  these  changes  is  very 
simple,  and  the  running  of  the  circuits  is  shown 
in  the  plan,  Fig.  102. 

Two  forms  of  brake  can  be  brought  into  play 
on  the  car  ;  the  ordinary  mechanical  and  the 
electrical  brakes.  The  latter  are  called  into 
action  automatically  when  the  switch  cuts  off 
the  battery  current.  The  motors  are  then  con- 
verted into  dynamos  which  generate  a  current 
that  is  sent  into  the  coils  on  the  brake-shoes, 
magnetizing  them  so  that  they  are  attracted  by, 
and  press  against,  the  wheels.  At  the  same 
time  the  resistance  encountered  by  the  arma- 
ture turning  in  the  magnetic  field  also  acts 
powerfully  to  retard  the  speed,  and  both  these 
acting  together  bring  the  car  rapidly  to  a  halt. 

We  may  add  that  Mr.  J.  Zacharias,  the  en- 
gineer of  the  company  undertaking  the  experi- 
ments, calculated  from  accepted  data  that  the 
running  of  such  a  tramway  by  electricity  in- 
stead of  horses  would  bring  about  a  saving  of 
fifty  per  cent,  in  the  yearly  expenses. 

At  the  Antwerp  Exhibition,  of  1885,  a  series 
of  most  interesting  tests  were  carried  out  on 
tramway  motors,  as  mentioned  above,  and  after 
four  months  of  trial  the  first  prize  was  awarded 
to  the  electric  car  driven  by  accumulators.  In 
a  paper  read  before  the  Society  of  Arts,  early  in 
the  present  year,  Capt.  Douglas  Galton,  the 
English  juror  upon  the  testing  committee,  gave 
a  resume  of  the  experiments,  which  rank 
among  the  most  interesting  and  important 
made  on  this  class  of  motors.  There  were  five 


USE  OF  STORAGE  BATTERIES  WITH  ELECTRIC  MOTORS. 


105 


different  motors  which  entered  upon  the  tests, 
and  they  may  be  divided  into  two  classes  as 
follows:  Three  were  propelled  by  the  direct 
action  of  steam,  and  two  were  propelled  by 
stored-up  force  supplied  from  fixed  engines. 

Propelled  by  the  Direct  Action  of  Steam. 

1.  The  Krauss  locomotive    engine  separated 
from  the  carriage. 

2.  The  Wilkinson  locomotive,  also  separated 
from  carriage. 

3.  The  Rowan  engine  and  carriage  combined. 

Propelled  by  Stored-up  Force. 

4.  The  Beaumont  compressed  air  engine. 

5.  The  electric  carriage.  ' 

We  give  below  the  principal  results  in  so  far 
as  they  relate  to  the  electric  car,  and  also  the 
tables  of  comparison  between  all  the  motors. 

In  the  electric  tram-car  the  haulage  was 
effected  by  means  of  accumulators.  The  car 
was  of  the  ordinary  type,  with  two  platforms. 
It  was  said  to  have  been  running  as  an  ordinary 
tram-car  since  1870.  It  had  been  altered  in  1884: 
by  raising  the  body  about  six  inches,  so  as  to 
lift  it  clear  of  the  wheels,  in  order  to  allow  the 
space  under  the  seats  to  be  available  for  re- 
ceiving the  accumulators,  which  consisted  of 
Faure  batteries  of  a  modified  construction. 
The  accumulators  employed  were  of  an  im- 
proved kind,  devised  by  M.  Julien,  the  under 
manager  of  the  Compagnie  1'Electrique,  which 
undertook  the  work.  The  principal  modifica- 
tion consists  in  the  substitution,  for  the  lead 
core  of  the  plates,  of  one  composed  of  a  new 
unalterable  metal.  By  this  change  the  resist- 
ance is  considerably  diminished,  the  electro- 
motive force  rises  to  2.40  volts,  the  return  is 
greater,  the  output  more  constant,  and  the 
weight  is  considerably  reduced.  The  plates 
being  no  longer  subject  to  -deformation,  have 
the  prospect  of  lasting  indefinitely.  The  ac- 
cumulators used  were  constructed  in  August, 
1884. 

An  experiment  was  made  on  October  21, 1884, 
to  ascertain,  as  a  practical  question,  what  was 
the  work  absorbed  by  the  Gramme  machine  in 
charging  the  accumulators.  The  work  trans- 
mitted from  the  steam  engine  was  measured 
every  quarter  of  an  hour  by  a  Siemens  dyna- 
mometer ;  at  the  same  time  the  current  and  the 
electromotive  force  given  out  by  the  machine, 
as  well  as  the  number  of  the  revolutions  it  was 


making,  were  noted.  It  resulted  that  for  a 
mean  development  of  four  mechanical  horse 
power,  the  dynamometer  gave  into  the  accumu- 
lators to  be  stored  up  2.28  electrical  horse  power, 
or  57  percent.  The  intensity  varied  between 
25.03  and  23.51  amperes  during  the  whole  time 
of  charging.  Of  this  amount  stored  up  in  the 
accumulators  a  further  loss  took  place  in  work- 
ing the  motor  ;  so  that  from  thirty  to  forty  per 
cent,  of  the  work  originally  given  out  by  the 
steam  engine  must  be  taken  as  the  utmost  use- 
ful effect  on  the  rail.  It  was  estimated  that  to 
draw  the  carriage  on  the  level  .714  horse  power 
was  required,  or  if  a  second  carriage  was 
attached,  .848  horse  power  would  draw  the  two 
together.  This  would  mean  that,  say,  two 
horse  power  on  the  fixed  engine  would  be  em- 
ployed to  create  the  electricity  for  producing 
the  energy  required  to  draw  the  carriage  on 
the  level.  The  electric  tram-car  was  quite  equal 
in  speed  to  those  driven  by  steam  or  compressed 
air,  and  was  characterized  by  the  noiselessness 
and  ease  with  which  it  was  manipulated. 

It  should  be  mentioned  that  the  car  was 
lighted  at  night  by  two  incandescent  lamps, 
which  absorbed  1.5  ampere  each ;  and  the 
brakes  also  were  worked  by  the  accumulators. 
The  weight  of  the  tram-car  was  5,054  pounds  ; 
the  weight  of  the  accumulators  was  2,460 
pounds ;  the  weight  of  the  machinery,  includ- 
ing dynamo,  1,232  pounds.  The  car  contained 
room  for  fourteen  persons  inside  and  twenty 
outside. 

The  original  programme  of  the  conditions 
which  were  laid  down  in  the  invitation  to  com- 
petitors, as  those  upon  which  the  adjudication 
of  merit  would  be  awarded,  contained  twenty 
heads,  to  each  of  which  a  certain  value  was  to 
be  attached  ;  and,  in  addition  to  these  special 
heads,  there  were  also  to  be  weighed  the  fol- 
lowing general  considerations,  viz. :  a.  The 
defects  or  inconveniences  established  in  the 
course  of  the  trials,  b.  The  necessity  or  other- 
wise of  turning  the  motor,  or  the  carriage  with 
motor,  at  the  termini,  c.  Whether  one  or  two 
men  would  be  required  for  the  management  of 
the  engine. 

As  regards  these  preliminary  special  points, 
the  compressed  air  motor,  as  well  as  the  Rowan 
engine,  required  to  be  turned  for  the  return 
journey,  whereas  the  other  motors  could  run  in 
either  direction.  In  regard  to  this,  the  electric 
car  was  peculiarly  manageable,  as  it  moved  in 


106 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


either  direction,  and  the  handle  by  which  it 
was  managed  was  always  in  front,  close  to  the 
brake.  The  carriage  was  the  only  one  which 
was  entirely  free  from  the  necessity  of  attend- 
ing to  the  fire  during  the  progress  of  the  journey, 
for  even  the  compressed  air  engine  had  its 
small  furnace  and  boiler  for  heating  the  air. 
Each  of  the  motors  under  trial  was  managed 
by  one  man. 

The  several  conditions  of  the  programme 
may  be  conveniently  classified  in  three  groups, 
under  the  letters  A,  B,  C.  Under  the  letter  A 
have  been  classed  accessory  considerations, 
such  as  those  of  safety  and  police.  These  are 
of  special  importance  in  towns.  But  their  rela- 
tive importance  varies  somewhat  with  the 
habits  of  the  people  as  well  as  with  the  require- 
ments of  the  authorities  ;  for  instance,  in  one 
locality  or  country  conditions  are  not  objected 
to,  which  in  another  locality  are  considered 
entirely  prohibitory.  The  conditions  under  this 
head  are: 

1.  Absence  of  steam.  2.  Absence  of  smoke 
and  cinders.  3.  Absence,  more  or  less  com- 
plete, of  noise.  4.  Elegance  of  aspect.  5.  The 
facility  with  which  the  motor  can  be  separated 
from  the  carriage  itself.  C.  Capacity  of  the 
brake  for  acting  upon  the  greatest  possible 
number  of  wheels  of  the  vehicle  or  vehicles.  7. 
The  degree  to  which  the  outside  covering  of 
the  motor  conceals  the  machinery  from  the 
public,  while  allowing  it  to  be  visible  and  ac- 
cessible in  all  parts  to  the  engineer.  8.  Facility 
of  communication  between  the  engineer  and 
the  conductor  of  the  train.  In  deciding  upon  the 
relative  merits  of  the  several  motors,  so  far  as 
the  eight  points  included  under  this  heading  are 
concerned,  it  is  clear  that,  except  possibly  as 
regards  absence  of  noise,  the  electrical  car  sur- 
passed all  the  others.  The  compressed  air  car 
followed,  in  its  superiority  in  respect  of  the 
first  three  points,  viz.,  absence  of  steam, 
absence  of  smoke,  and  absence  of  noise  ;  but 
the  Rowan  was  considered  superior  in  respect 
of  the  other  points  included  in  this  class. 

Under  letter  B  have  been  classed  the  con- 
siderations of  maintenance  and  construction. 

9.  Protection,  more   or   less  complete,  of   the 
machinery  against  the  action  of  dust  and  mud. 

10.  Regularity  and  smoothness  of  motion.     11. 
Capacity    for    passing   over    curves    of    small 
radius.     12.  The    simplest    and  most    rational 
construction.     13.  Facility  for   inspecting  and 


cleaning  the  interior  of  the  boilers.  14.  Dead 
weight  of  the  train  compared  with  the  number 
of  seats.  15.  Effective  power  of  traction  when 
the  carriages  are  completely  full.  1C.  Rapidity 
with  which  the  motor  can  be  taken  out  of  the 
shed  and  made  ready  for  running.  17.  The 
longest  daily  service  without  stops  other  than 
those  compatible  with  the  requirements  of  the 
service.  18.  Cost  of  maintenance  per  kilometre. 
(It  was  assumed,  for  the  purpose  of  this  sub- 
heading, that  the  motor  or  carriage  which  gave 
the  best  results  under  the  conditions  relating  to 
paragraphs  9,  10,  12,  and  13,  would  be  least 
costly  for  repairs.) 

As  regards  the  first  of  these,  viz.,  protection 
of  the  machinery  against  dirt,  the  machinery 
of  the  electrical  car  had  no  protection.  It  was 
not  found  in  the  experiments  at  Antwerp  that 
inconvenience  resulted  from  this  ;  but  it  is  a 
question  whether  in  very  dusty  localities,  and 
especially  in  a  locality  where  there  is  metallic 
dust,  the  absence  of  protection  might  not  entail 
serious  difficulties,  and  even  cause  the  destruc- 
tion of  parts  of  the  machinery. 

In  respect  of  the  smoothness  of  motion  and 
facility  of  passing  curves,  the  cars  did  not  pre- 
sent very  material  differences,  except  that  the 
cars  in  which  the  motor  formed  part  of  the  car 
had  the  preference. 

In  the  case  of  simplicity  of  construction,  it  is 
evident  that  the  simplest  and  most  rational  con- 
struction is  that  of  a  car  which  depends  on 
itself  for  its  movement,  which  can  move  in 
either  direction  with  equal  facility,  which  can 
be  applied  to  any  existing  tramway  without 
expense  for  altering  the  road,  and  the  use  of 
which  will  not  throw  out  of  employment 
vehicles  already  used  on  the  lines  ;  the  electric 
car  fulfilled  this  condition  best,  as  also  the  con- 
dition numbered  13,  as  it  possessed  no  boiler. 

In  respect  to  No.  14,  viz.,  the  ratio  of  the  dead 
weight  of  the  train  to  passengers,  if  we  assume 
154  pounds  as  the  average  weight  per  passen- 
ger, the  following  is  the  result  in  respect  of 
the  three  cars  in  which  the  power  formed  part 
of  the  car: 


Electric  car, , 


9,350  Ibs. 


Rowan, 

Compressed  air,     .     . 


154  X  34 

15,9511  11.,. 
154  X  45 

22,000  Ibs. 
154  X  56 


'  =  1.78. 


=  2.30. 


2.5&. 


USE  OF  STORAGE  BATTERIES  WITH  ELECTRIC  MOTORS. 


107 


The  detached  engine  gave,  of  course,  less 
favorable  results  under  this  head. 

Under  head  No.  15  the  tractive  power  of  all 
the  motors  was  sufficient  during  the  trials,  hut 
the  line  was  practically  level,  therefore  this 
question  could  only  be  resolved  theoretically, 
so  far  as  these  trials  were  concerned,  and  the 
table  before  given  affords  all  the  necessary 
data  for  the  theoretical  calculation. 

As  regards  th  3  rapidity  with  which  the 
motors  could  be  brought  into  use  from  standing 
empty  in  the  shed,  the  electric  car  could  receive 
its  accumulators  more  rapidly  than  could  the 
boiler  be  brought  into  use  for  heating  the  ex- 
haust of  the  compressed  air  car. 

Under  letter  C  are  classed  considerations  of 
economy  in  the  consumption  of  materials  used 
for  generating  the  power  necessary  for  work- 
ing. 


TABLE  I. 


TABI.K  II. 


B§ 

ri 

Br 

.0? 

| 

a,w  p 

\l 

o 

la 

?  ~  a 

W 

i 

II  a 

I 

"S 

Description  of 

~  =. 

D 

^ 

F 

^  c^ 

c' 

~  ~  -/J 

motor. 

I 

5 

! 

v  -. 

0 

Hr-? 

r 

i  ~ 

^»> 

?5I 

3 

I 

s  s 

i" 

-i  &  n 

0 

a 

5 

II 

r^ 

s  ='§ 

Klectrifi  

2,358.9 

Lbs. 
14,,  80 

(i.lii 

80,203.5 

Lbs. 

14,780 

.18 

2,010.9 

M.4!IK 

5.12 

148,399.1! 

14.498 

.09 

Wilkinson   .... 

2.473.322.00H 

8.82 

119.085.1 

22,000 

2,457.8  "•'  '•><< 

9.10 

108,983.9  •>•>  "°fi 

.20 

Compressed  air    . 

2.259.1 

90,420 

39.48 

128,189.3 

90,420 

.69 

TABLE   III. 


TABI.K  IV. 


? 

g 

H.? 

-g 

§ 

§ 

p 

I 

?ia 

§£ 

.=£ 

M  i 

M» 

"5 

s^i 

S 

C 

Es 

2  <r| 

Description   of 

P 

o' 

"  ~  •  ' 

S 

O" 

•        •        Q 

motor. 

^ 

•5  a 

ffl 

-  = 
-"1 

B 

1 

a 
>-tj 

gS1 

1 

a 

rf 

•sa 

"*  £ 

_ 

c 

D 

o 

3 

'    5 

*S  0 

3  i? 

5* 

•-.-, 

I 

a 

_  .  v 

61,591.2 

Lbs. 

1  4,786 

.23 

2,358.9 

1-1)8. 

99.0 

.038 

Rowan   

135,928.8 

14,498 

.10 

2,6ie!9 

1067 

.038 

Wilkinson    .... 

93,965.6 

22.000 

.23 

2.  157.8 

188.5 

.073 

86,039.9 

.).)  7*>(J 

.25 

2,473.3 

255.4 

.101 

Compressed  air    . 

132,732.7 

90^420 

.66 

2^S».t 

585.2 

366 

As  regards  the  figures  in  these  tables,  it  is  to 
be  observed  that  the  consumption  of  fuel  for 
the  electric  car  is,  to  a  certain  extent,  an  esti- 
mate ;  because  the  engine  which  furnished  the 
electricity  to  the  motor  also  supplied  electricity 


for  electric  lights,  as  well  as  for  an  experi- 
mental electric  motor  which  was  running  on 
the  lines  of  tramway,  but  was  not  brought  into 
competition.  Capt.  Galton  summarized  his 
views  as  follows: 

"  The  general  conclusion  to  which  these  ex- 
periments lead  is  that,  undoubtedly,  if  it  could 
certainly  be  relied  upon,  the  electric  car  would 
be  the  preferable  form  of  tramway  "motor  in 
towns,  because  it  is  simply  a  self-contained 
ordinary  tram-car,  and  in  a  town  the  service  re- 
quires a  number  of  separate  cars,  occupying  as 
small  a  space  each  as  is  compatible  with  accom- 
modating the  passengers,  and  which  follow 
each  other  at  rapid  intervals.  But  the  practica- 
bility and  the  economy  of  a  system  of  electric 
tram-cars  has  yet  to  be  proved  ;  for  the  experi- 
ments at  Antwerp,  while  they  show  the  perfec- 
tion of  the  electric  car  as  a  means  of  conveyance, 
have  not  yet  finally  determined  all  the  questions 
which  arise  in  the  consideration  of  the  subject. 
For  instance,  with  regard  to  economy,  the 
engine  employed  to  generate  the  electricity 
was  not  in  thoroughly  good  order,  and  from  its 
being  used  to  do  other  work  than  charging  the 
accumulators  of  the  tram-car,  the  consumption 
of  fuel  had  to  be  to  some  extent  estimated.  In 
the  next  place,  the  durability  of  the  accumu- 
lators is  still  to  be  ascertained  ;  upon  this  much 
of  the  economy  would  depend.  And  in  addition 
to  this  question,  there  is  also  that  of  the  dura- 
bility of  parts  of  the  machinery  if  exposed  to 
dust  and  mud." 

As  electricity  was  thus  awarded  the  first  prize, 
we  cannot,  therefore,  complain,  but  we  might 
show  that  the  conditions  were  very  unfavorable 
for  good  results,  and  this  is  evident  when 
glancing  at  the  consumption  of  fuel.  We  find 
the  electric  railway  requiring  nearly  twice  as 
much  coal  as  one  of  the  steam  locomotives,  and 
about  an  equal  quantity  with  another  steam 
motor.  The  report  itself  explains  how  this  is 
to  be  accounted  for — other  electrical  service 
being  rendered— and  we  may  add  that  the  test, 
if  more  minutely  carried  out,  would  have  shown 
a  far  greater  efficiency  for  the  electric  system 
than  appears  from  the  report.  This  assertion 
is  based  upon  several  facts.  In  the  first  place, 
the  engine  which  was  employed  in  driving  the 
dynamo  which  charged  the  accumulators,  was 
a  portable  one,  the  economy  of  which  was  not 
determined.  A  good  stationary  engine  would 
in  all  probability  have  yielded  better  results. 


108 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


Starting  with  an  indifferent  engine,  the  charg- 
ing dynamo  is  found  to  have  an  efficiency  of 
only  fifty-seven  per  cent. ,  a  figure  far  helow  that 
attained  every  day  in  practical  work  by  all 
leading  types  of  American  dynamo  slectric 
machines.  What  the  efficiency  of  the  motor 
upon  the  car  was,  is  not  stated,  but  it  is  evident 
that  if  its  efficiency  was  low,  another  factor 
against  the  system  is  introduced.  If,  therefore, 
the  consumption  of  fuel  was  high,  it  cannot  be 
wondered  at,  as  the  causes  are  apparent.  It 
would  not  be  asserting  too  much  to  say  that 
with  a  good  engine,  dynamo,  and  motor  the 
coal  consumption  could  have  been  reduced  one- 
half,  so  that  even  in  this  respect  the  electric 
propulsion  would  be  equal,  if  not  superior,  to 
steam  direct.  What  makes  this  trial  all  the 
more  interesting  is  the  fact  that  accumulators 
have  been  found  to  give  satisfactory  service  in 
a  trying  position,  for  none  can  deny  that  the 
constant  handling  and  necessary  rough  usage 
are  far  from  conducive  to  the  good  standing 
and  long  life  of  the  storage  battery.  It  appears 
from  the  report  that  the  accumulators  employed 
were  constructed  in  August,  1884.  If  they  were 
in  use  all  that  time  and  yet  gave  the  service 
they  did  during  the  test,  it  is  again  evident 
that  the  storage  battery  has  entered  upon  its 
commercial  sphere  of  usefulness.  Instances  of 
this  kind,  substantiating  the  durability  of  the 
battery,  are  cropping  up  almost  daily,  and  the 
fact  is  dawning  upon  the  world  that  the  storage 
battery  is  not  a  name  but  a  reality. 

In  this  connection  the  work  of  Mr.  A.  H. 
Bauer,  of  the  Electric  Storage  Company,  of 
Baltimore,  deserves  notice.  During  1885  a  very 
successful  experiment  was  made  by  him  on  one 
of  the  Daft  motor  cars,  for  the  purpose  of  dem- 
onstrating the  practicability  of  secondary  bat- 
teries for  street  car  propulsion.  Since  then 
Mr.  Bauer  has  devised  a  novel  system  that  can 
be  applied  to  existing  cars  at  a  very  small  ex- 
pense. An  experimental  car  equipped  with  the 
system  has  been  running  for  some  time  on  an 
eighth-of-a-mile  track  at  the  Viaduct  Manu- 
facturing Company's  works. 

Unlike  other  experimenters,  instead  of  using 
light-weight  cars  for  his  test,  Mr.  Bauer  has 
attacked  the  problem  from  the  opposite  side ; 
that  is  to  say,  he  has  begun  with  larger  weights 
than  would  appear  in  practice. 

The  car  used  is  an  old  one  loaned  by  the 
Union  Railway  Company,  is  twenty  feet  in 


length  and  weighs  5,400  pounds.  The  equip- 
ment consists  of  two  beams  extending  from 
one  axle  to  the  other.  These  beams  carry  a 
motor,  the  armature  shaft  being  extended  and 
having  pinions  on  each  end  which  mesh  into 
counter  gears.  The  countershaft  carries  a 
pinion,  which  in  turn  meshes  into  a  gear  on  the 
car  axle.  The  motor  is  wound  in  three  sections 
in  multiple  arc,  and  is  connected  with  a  double 
switch  located  on  the  platform  for  throwing 
one,  two,  or  three  of  the  sections  in  circuit  with 
the  battery,  as  desired,  depending,  of  course, 
upon  the  amount  of  power  the  motor  is  required 
to  develop. 

To  accommodate  the  batteries,  which  are 
placed  under  the  seats  and  are  entirely  out  of 
sight,  the  body  of  the  car  is  raised  three  inches, 
so  as  to  bring  the  wheels  below  the  floor.  The 
batteries  are  set  on  trays  upon  rollers,  and 
when  necessary  to  make  changes  they  can  be 
run  out  on  to  platforms  through  doors  in  the 
sides  of  the  car,  and  freshly  charged  ones  run 
in.  This  can  be  done  within  the  time  required 
to  change  horses.  Access  to  the  motor  and 
gearing  is  had  through  a  trap-door  in  the  floor, 
or  they  can  be  got  at  from  underneath  the  car. 

The  weights  of  the  different  parts  of  the  ex- 
perimental car  are  as  follows  : 

Lbs. 

Car 5,400 

CO  cells  battery, 5,400 

Motor, 923 

Gearing, 900 

Total, 12,6'.»3 

or  about  6£  tons. 

In  practice  the  above  total  weight  will  be  re- 
duced to  about  7,500  pounds. 

The  whole  car,  internally  and  externally,  has 
nothing  whatever  strange  in  its  appearance  ;  it 
looks  indeed  similar  to  an  ordinary  street  car 
propelled  without  horses  or  other  visible  motive 
power. 

The  track  is  one-eighth  of  a  mile  in  length,  be- 
ginning at  the  car-house  at  the  foot  of  a  one  in 
twenty  grade,  200  feet  in  length,  on  a  curve  of 
forty-five  feet  radius.  As  already  stated,  this 
car  has  been  running  almost  daily  for  about  two 
months.  With  the  exception  of  a  bolt  or  collar, 
worLing  loose,  not  a  single  fault  has  developed, 
the  car  running  smoothly  and  satisfactorily 
during  every  trip. 

When  running  at  a  speed  of  six  miles  per 
hour,  the  armature  makes  800  revolutions  per 


USE  OF  STORAGE   BATTERIES   WITH  ELECTRIC   MOTORS. 


109 


minute.  With  5,400  pounds  of  battery  the  car 
will  continue  to  run  without  cessation  for  six 
hours  at  a  speed  of  six  miles  per  hour;  or  a 
total  of  thirty-six  miles.  Tests  have  also  been 
made  with  half  horse-power  cells  having  a  total 


FIG.  103. — GKARIXX  OF  KLIESON  CAIJ. 

weight  of  2,580  pounds,  running  continuously 
for  three  hours,  or  eighteen  miles,  before  requir- 
ing to  be  changed. 

Calculations  based  on  the  efficiency  of  the 
above-mentioned  and  other  trials,  show  that 
the  cost  of  running  a  line  of  street  cars 
equipped  with  the  Bauer  system  should  not  ex- 
ceed $2.21  per  car  per  day.  The  average  cost 
of  horsing  is  understood  to  be  $4  per  car  per 
day.  Given  a  line  running  say  twenty-four 
cars  it  will  be  seen  that  by  substituting  this 
system  or  any  analogous,  a  saving  of  $1.79 
per  day  per  car  should  be  effected.  This 
for  twenty-four  cars  amounts  to  $15,080  per 
annum,  a  sum  that  at  six  per  cent,  represents 
the  interest  on  $201,340. 

In  Figs.  103,  104,  and  105  is  illustrated  the 
method  of  Mr.  Elieson,  put  in  operation  by  the 
Electric  Locomotive  and  Power  Company, 
London.  The  novelty  in  the  apparatus  consists 
in  the  arrangement  of  the  gearing  by  which 
the  motor  can  be  driven  at  a  very  high  velocity, 
and  thus  work  under  favorable  conditions  for 
economy. 

The  mechanical  connection  of  the  motor  is 
very  ingenious.  Mr.  Elieson  has  applied  a 
lever  between  the  electro-motor  and  the  axle  of 

14 


the  locomotive  in  such  a  way  that  the  motor, 
which  must  necessarily  run  at  a  high  rate  of 
speed  in  order  to  develop  the  greatest  efficiency, 
acts  through  the  lever  by  a  method  analogous 
to  the  case  of  a  man  using  a  crowbar  for  the 
purpose  of  lifting  a  heavy  weight.  By  this  con- 
trivance the  vis  inertia  of  the  loaded  tram-car 
is  easily  overcome,  and  it  is  evident,  even  to 
non-scientific  readers,  that  speed  is  then  easily 
attained  until  the  natural  speed  of  the  electro- 
motor is  approached  by  the  rate  of  speed  of  the 
driving  wheels. 

Instead  of  the  electro-motor  being  a  fixture, 
and  having  motion  transmitted  from  it  through 
belt  or  crank  gearing  to  the  wheels  of  the  car, 
the  motor  itself  revolves,  the  motion  being  trans- 
mitted through  bevel  gearing.  It  has,  as  will 
be  seen.  Figs.  100  and  101,  a  vertical  shaft 
through  its  centre,  to  which  a  motion  lever  pro- 
jecting horizontally  about  two  feet,  and  carry- 
ing at  its  outer  end  a  spur-wheel  gearing  into  a 
fixed  circular  rack,  is  secured.  This  vertical 
shaft  carries  at  its  lower  end  a  bevel  wheel, 
which  gears  into  one  or  other  of  .two  similar 
wheels  on  the  driving  axle  of  the  engine.  The 
mitre  gearing  is  equipped  with  a  mechanical 


Fio.  104. — GEAKING  OF  EMESON  CAR. 

clutch,  by  means  of  which  the  locomotive  may 
be  made  to  run  either  backward  or  forward,  a 
lever,  acting  mechanically,  throwing  the  motor 
in  or  out  of  gear,  or  adjusting  the  clutch  by  a 
simple  movement  of  the  hand.  This  suggests 
itself  as  being  a  very  good  arrangement  indeed. 
The  electrical  details  are  very  simple.  The 
motor  is  fitted  with  collecting  brushes  travelling 
on  two  fixed  circular  rings  of  copper,  separated 


110 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


from  each  other  by  a  flange.  The  speed  of  the 
motor  is  varied  by  inserting  resistances  in  the 
ordinary  way,  and  it  is  evident  that  great  care 
has  been  exercised  to  avoid  anything  like  com- 
plexity. The  locomotive,  Fig.  102,  in  ap- 
pearance resembles  a  small  car,  and  weighs  four 
tons  seventeen  cwt.  The  motor,  which  is  of 
four  horse  power,  consumes  about  forty  amperes 
per  hour,  so  that  it  carries  power  sufficient  for 
six  or  seven  hours  of  motion,  and  makes  about 
600  revolutions  per  minute  when  in  full  swing, 
or  a  maximum  of  1,000  on  a  level  road.  The 


FIG.  105. — ELIESON  CAU  WITH  ACCUMULATORS. 

speed  obtained  is  eight  miles  per  hour,  it  being 
for  certain  obvious  reasons  not  desirable  to  ex- 
ceed this  rate.  Fifty  storage  cells  are  used, 
giving  280  ampere  hours. 

Mr.  Reckenzaun  has  recently  applied  elec- 
tricity to  the  haulage  of  coal  in  the  Trafalgar 
collieries  of  Drybrook,  Gloucestershire,  En- 
gland, and  some  recent  tests  made  with  the 
motor  are  of  considerable  interest,  as  they 
show  a  remarkable  uniformity  of  action  under 
various  loads,  together  with  a  high  efficiency. 
A  view  of  the  locomotive  now  in  use  is  given 
in  Fig.  100.  The  construction  of  the  motor  and 
driving  gear  is  similar  to  that  adopted  by  the 
inventor  in  his  electric  street  cars,  but  the  condi- 
tions to  be  satisfied  were  widely  different  from 
and  more  difficult  than  those  obtaining  in  an  or- 
dinary tramway.  The  space  is  very  limited, 
and  since  both  sharp  curves  and  heavy  gradi- 


ents occur  at  frequent  intervals,  it  was  some- 
what difficult  to  stow  away  the  necessary 
power  in  so  limited  a  space.  Within  the  nar- 
row gauge  of  H  feet  7  inches,  and  an  extremely 
short  wheel  base,  there  had  to  be  arranged  an 
electric  motor  of  eight  horse  power,  with  suitable 
gearing,  brakes,  and  attendant  details.  There 
is  a  foot-board  which  runs  all  round  the  loco- 
motive, and  there  is  a  brake  lever  at  each  end. 
The  box  forming  the  body  of  the  car  serves  to 
receive  the  accumulators,  and  there  is  a  com- 
pound switch  at  each  end  by  which  the  motor 
can  be  started,  stopped,  and  reversed  by  the 
attendant  who  stands  at  one  end  or  the  other 
of  the  foot-board,  according  to  the  direction  in 
which  the  locomotive  is  travelling.  The  switches 
are  inclosed  in  a  box  to  protect  them  from  ac- 
cidental injury. 

At  the  test,  electrical  energy  was  supplied  to 
the  motor  from  a  number  of  "  E.  P.  S."  storage 
cells,  and  the  mechanical  work  was  ascertained 
by  means  of  a  balanced  Prony  brake.  The 
following  table  gives  the  results  of  the  test: 


S 

Kleclrh'Hl 

Prony 

3 

measurements. 

brake. 

G 

£ 

Electrical 

Meclifin- 

b 

S 

. 

fc 

V 

energy. 

iciil  work 

I 

1 

I 

V 

o 

*i 

a 

- 

— 

"J 

Horse 

1 

.2 

— 

*c  ** 

5  . 

power 

Horse 

fl 

tJ  * 

.—  V 

-  ^ 

£  X  C 

power 

c 
6 

1 

V 

J 

[o 

fi 

fa 

P 

746 

8 

g 

1 

1.020 

105 

35.5 

2.(i2.-> 

7 

4.98 

:;.5G8 

71.65 

2 

1,013 

107 

40.0 

8 

5.73 

4.027 

70.50 

8 

982 

104.75 

39.5 

8 

5.55 

8.930 

70.8 

4 

860 

95.5 

43.25 

9 

5.53 

3.870 

70.0 

B 

970 

106.5 

43.0 

!) 

6.14 

4.3S5 

71.4 

6 

000 

101.78 

46  75 

10 

6.38 

4.500 

705 

7 

1,022 

113.0 

47.0 

10 

7.15 

4.110 

71,1 

8 

1,048 

114.88 

47.75 

10 

7.88 

5.240 

71.3 

9 

1,047 

121.88 

53.0 

12 

8.86 

6.282 

725 

10 

1,070 

122.64 

54.0 

12 

8.87 

6.420 

72.3 

11 

950 

113.87 

62.0 

14 

9.46 

6.650 

70.3 

12 

1,040 

127.7 

72.0 

* 

17 

12..-.2 

8.85 

71.8 

In  the  motor  tested  there  are  only  two  brushes 
used  (one  pair),  which  were  not  shifted  or  ad- 
justed during  the  tests.  The  motor  is  so  de- 
signed that  the  brushes  remain  fixed  in  posi- 
tion, and  the  direction  of  rotation  of  the  arma- 
ture is  controlled  by  merely  reversing  the 
direction  of  the  current.  Electricity  has  for 
some  time  been  successfully  applied  in  these 
mines  for  pumping  water  and  for  ventilating, 
and  it  is  now  intended  to  supplant  the  horses 
used  in  the  haulage  of  the  coal. 


USE   OF  STORAGE  BATTERIES  WITH   ELECTRIC  MOTORS. 


Ill 


There  has  now  entered  upon  active  duty  at 
Hamburg,  Germany,  a  tram-car  which  obtains 
its  power  from  accumulators  carried  by  it. 
Herr  Huber,  the  engineer  in  charge,  was  one  of 
the  members  of  the  board  which  awarded  the 
tram-car  run  by  the  Julien  accumulators  at  the 
Antwerp  Exhibition,  the  first  prize,  in  competi- 
tion with  several  other  forms  of  locomotors. 
He  is  evidently  willing  to  practise  what  he  be- 
lieves. 

The  Hamburg  car,  which  will  soon  be  supple- 
mented by  others,  weighs,  fully  equipped, 


and  can  easily  be  drawn  out  by  opening  two 
long  traps  in  the  side  of  the  car.  In  the  car 
house  the  vehicle  is  drawn  between  two  tables, 
on  which  the  charging  takes  place,  and  the  ac- 
cumulators are  slid  from  the  car  on  to  the 
tables.  The  shunting  of  the  boxes,  both  in  the 
car  and  on  the  charging  table,  takes  place 
automatically  by  a  contact  apparatus,  both 
simple  and  sure,  constructed  by  Herr  Huber. 

Four  double  conductors  lead  from  the  ac- 
cumulators in  the  car,  which  are  shunted  in 
four  groups,  to  the  Julien  commutators,  of 


FIG.  106. — KKCKKNZAUN  MINIM;   LIX-OMOTIVK. 


4,830  kilogrammes.  Of  this  weight,  1,200  kilo- 
grammes is  that  of  the  accumulators.  The 
accumulator  consists  of  ninety-six  cells,  of 
which  every  three  are  united  in  a  single 
three-cell  holder.  The  cells  are  formed  out  of 
a  new  material,  something  like  hard  gutta 
percha,  but  rather  more  flexible.  Each  cell 
contains  fifteen  plates,  seven  positive  and  eight 
negative.  The  plates  have  a  surface  of  only 
1:54  by  147  millimetres,  and  are  about  four 
millimetres  thick.  The  charging  requires  about 
eight  hours. 

The  accumulators  are  distributed  in  eight  low 
wooden  boxes,  of  which  four  are  stowed  away 
on  each  side  of  the  car  in  the  space  under  the 
seats.  The  boxes  move  along  greased  slides, 


which  one  is  placed  on  each  platform.  By 
turning  a  handle  which  forms  part  of  the  key 
of  the  commutator,  six  different  positions  can 
be  given  to  it,  viz.: 

(1)  So  that  there  is  no  connection  between  the 
accumulators  and  the  motor.  (2)  The  four 
groups  of  accumulators  are  connected  in  par- 
allel arc  and  placed  in  connection  with  the 
motor.  (3)  The  groups  are  connected  two  and 
two  in  parallel  arc,  and  the  two  pairs  in  series 
and  in  connection  with  motor.  (4)  Two  in 
parallel  arc  behind  the  other  two  in  series.  (5) 
All  four  groups  in  series.  (6)  All  four  groups 
in  parallel  arc,  but  unconnected  with  the  mo- 
tor. The  commutator  stands  in  this  position 
with  the  key  up  during  the  periods  of  stoppage. 


112 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


A  great  advantage  of  this  arrangement  is 
that  different  velocities  are  obtained  without 
the  application  of  any  current  regulator  or  re- 
sistances. 

The  positions  (2),  (3),  (4),  (5)  of  the  key  cor- 
respond to  the  electromotive  forces  48,  96,  144, 


mits  its  power  by  means  of  hemp  cords  to  a 
loose  axle  between  the  two  wheel  axles,  and 
from  hence  the  power  is  given  out  by  means  of 
chains  to  the  wheel  axles.  The  hempen  ropes 
are  protected  as  much  as  possible  against  the 
influences  of  weather  by  a  special  preparation. 


FIG.  107. — CHARGING  STATION,  HAMHUKG  ELECTRIC  STRKET  RAILWAY. 


and  192  volts  on  the  motor,  and  its  veloc- 
ity again  corresponds  to  these  electromotive 
forces.  The  normal  current  amounts  to  about 
eighteen  amperes,  while  on  inclines  and 
curves  the  current  may  sometimes  reach  eighty 
amperes.  The  motor  is  a  Siemens  series  ma- 
chine, model  D,  with  about  0.0  ohm  resist- 
ance. It  is  hung  under  the  car  and  trans- 


The  reversal  of  the  direction  of  rotation  of 
the  machine  is  brought  about  by  changing  the 
position  of  the  brushes;  there  are  two  pairs  of 
brushes  about  ninety  degrees  apart,  of  which 
only  one  pair  rubs  at  one  time. 

One  charging  is  sufficient  to  drive  the  car  fifty 
kilometres.  Since  such  a  car  has  to  traverse 
about  100  kilometres  daily,  one  change  of  the 


USE  OF  STOKAGE  BATTERIES   WITH   ELECTRIC   MOTORS. 


113 


FIG.  108.— CAB,  HAMBURG  ELECTKIC  STRKKT  RAILWAY. 


accumulators  is  enough.     Fig.   107  shows  the 
charging  station,  Fig.  108  the  car. 

The  installation  for  charging  the  batteries 
occupies  but  a  very  small  space.  A  small  ver- 
tical steam  engine  is  mounted  on  the  wall  and 
belts  to  a  countershaft  which  drives  a  dynamo 


of  the  Schwerd  pattern.  In  addition,  there  are 
a  Buss  speed  indicator  and  the  necessary  volt- 
meters and  ammeters. 

The  use  of  electric  motors  with  storage  bat- 
teries, for  marine  and  aerial  navigation,  is 
treated  in  another  chapter. 


CHAPTBR  VIII. 


THE  INDUSTRIAL  APPLICATION   OK  ELECTRIC   MOTORS  IN 

EUROPE. 


THE  Paris  Electrical  Exposition  of  1881  was 
marked  by  a  revival  of  interest  in  electric  mo- 
tors, and  many  of  the  new  types  produced  were 
of  great  merit,  though  the  rapid  advances  in 
this  field  may  have  relegated  some  to  obscurity. 
One  of  the  best  known  is  the  machine  of  M. 
Paul  Jablochkoff,  which  he  calls  the  "  ecliptic," 
Fig.  109.  The  construction  of  the  "  ecliptic  "  is 


FIG.  109. — JABLOCHKOFF  MOTOR. 

said  to  realize  an  improvement  by  reducing  the 
mass  of  magnetic  metal  which  is  subjected  to 
changes  of  polarity,  whereby  the  magnetic  in- 
ertia is  reduced  to  the  lowest  possible  limit. 

This  motor  is  composed  essentially  of  two 
coils,  one  of  which  is  stationary  and  disposed 
in  a  vertical  plane,  while  the  other  is  movable 
and  fastened  to  a  horizontal  axis  in  an  inclined 
position.  It  is  from  this  inclination,  resembling 
that  of  the  ecliptic  to  the  equator,  that  the 
name  given  to  the  machine  by  the  inventor  is 
derived.  The  stationary  coil,  while  fixed  in 


the  vertical  plane,  is  not  in  a  plane  perpendicu- 
lar to  that  of  the  axis  of  rotation,  but  forms 
with  that  plane  a  certain  angle,  determined  by 
experiment,  and  which  depends  011  the  working 
conditions  of  the  apparatus. 

The  stationary  coil  is  wrapped  around  a  cop- 
per framework  ;  the  movable  one  is  fixed  upon 
an  iron  core,  which,  when  a  current  is  passed 
through  the  coil,  becomes  an  electro-magnet, 
the  poles  of  which  are  formed  by  two  circular 
discs.  A  commutator  is  placed  on  the  revolv- 
ing shaft,  against  which  four  brushes  bear. 
This  commutator  is  so  arranged  that  during 
the  revolution  of  the  shaft  the  movable  coil  is 


FIG.  110. 

traversed  by  a  current  always  in  one  direction, 
and  which  maintains  a  constant  polarity  in  the 
discs  of  the  electro-magnet,  but  at  each  half- 
revolution  the  current  is  reversed  in  the  sta- 
tionary coil,  which  has  no  soft  iron  core. 

The  motor,  then,  is  operated  by  the  reciprocal 
attractions  and  repulsions  between  a  movable, 
constant  electro-magnet,  and  a  fixed  solenoid, 
traversed  by  currents  alternately  in  opposite  di- 
rections. These  reciprocal  actions  tend  to  pro- 
duce a  rotation  of  the  movable  electro-magnet 
placed  in  the  interior  of  the  fixed  solenoid. 
The  object  of  the  commutator  is  to  make  these 
actions  co-operate  in  the  same  direction,  thereby 
producing  a  continuous  movement. 

M.  Jablochkoffs  motor  is  reversible  in  the 
true  sense  ;  that  is,  it  can  not  only  convert  elec- 
tricity into  mechanical  work,  but  can  also  con- 
vert mechanical  work  into  electricity. 


INDUSTRIAL  APPLICATION  OF   ELECTRIC   MOTORS   IN   EUROPE. 


115 


The  work  of  M.  Marcel  Deprez  with  electric 
motors,  large  and  small,  has  always  been  full  of 
interest  and  instruction.  Deprez  has  aimed  di- 
rectly at  higher  efficiency  while  avoiding  com- 
plicated construction.  He  observed  the  fact 
that  in  ordinary  motors  of  the  old  Siemens  type 
about  one-third  of  the  energy  expended  is  con- 
sumed in  energizing  the  magnetic  field  and 
in  maintaining  its  power.  He  therefore  con- 


this  plan,  having  an  internal  resistance  of  .5 
ohm  and  producing  an  electromotive  force  of 
nearly  twenty  volts,  with  a  total  weight  of  only 
twenty-five  kilogrammes  (fifty  pounds).  Such 
a  generator  would  give  a  carbon  pencil  four 
millimetres  in  diameter  and  fifty  millimetres 
(two  inches)  long,  a  bright  cherry  red  glow. 
M.  Deprez  found  that  the  use  of  such  a  mag- 
netic field  was  attended  with  difficulties,  how- 


Fin.  111. — DKPUEZ'S  SMALL  MOTOR. 


ceived  the  idea  of  using  permanent  magnets 
for  the  magnetic  field.  He  made  comparative 
tests  of  two  machines,  in  one  of  which  the  field 
magnets  were  permanent,  and  by  measuring 
the  power  obtained  and  the  amount  of  zinc  con- 
sumed in  the  battery  he  discovered  that  the 
efficiency  of  the  motor  having  permanent  mag- 
nets was  about  sixty  per  cent,  higher  than  that 
of  the  other.  M.  Deprez  found  on  using  this 
motor  as  a  dynamo-electric  machine  that  its 
electrical  equivalent  for  the  same  power,  as 
used  on  the  other  machine,  was  very  much 
higher.  He  constructed  a  small  generator  on 


ever.  Just  as  the  poles  of  an  armature  A  B 
(Fig.  110)  move  into  line  with  the  poles  of  the 
magnetic  field  N  S,  the  current  is  reversed  in 
the  armature,  and  instead  of  attraction  repul- 
sion results.  Now,  if  the  current  in  the  arma- 
ture is  too  powerful,  the  magnetism  of  the 
armature  will  be  sufficient  to  neutralize  the 
polarity  of  the  permanent  magnets,  even  when 
the  best  magnets  are  used.  The  result  was 
that,  although  the  efficiency  of  the  motor  was 
very  great  at  first,  the  power  of  the  motor  soon 
dwindled  down  by  the  weakening  of  the  mag- 
net. Another  disadvantage  of  permanent  mag- 


116 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


nets  was  that  for  the  same  power  they  must  be 
much  larger  than  electro-magnets.  M.  Deprez, 
therefore,  concluded  to  sacrifice  economy  in 
favor  of  convenience  to  sqme  extent,  and  re- 
turned to  electro-magnets,  striving  to  use  them 
to  the  best  advantage. 

Figs.  Ill  and  112  are  full  size  illustrations  of 
a  small  motor  constructed  by  M.  Deprez,  which 
will  run  a  small  sewing  machine  with  two  Bun- 


brushes  E  F  E'  ¥'  are  supported  by  small 
wooden  or  vulcanite  arms  attached  to  the  backs 
of  the  electro-magnets,  which  are  secured  to 
the  base  board,  as  shown,  and  form  the  supports 
for  the  whole  apparatus.  These  brushes  are 
made  long  and  flexible,  so  as  to  provide  a  light 
yet  smooth  and  perfect  contact  with  the  com- 
mutator segments.  The  speed  of  the  motor  is 
reduced  by  means  of  a  pinion  gearing  with  ? 


FIG.  112. — DEPRKZ'S  SMALL  MOTOR. 


sen  cells.  Two  armatures  C  C'  are  mounted  on 
the  same  shaft,  each  of  which  revolves  in  the 
magnetic  field  between  the  two  opposite  poles 
A  B'  and  B  A'  of  two  U  electro-magnets  placed 
opposite  each  other.  These  armatures  are  six- 
teen millimetres  in  diameter  and  twenty  milli- 
metres long,  and  are  fastened  to  the  shaft  with 
their  poles  at  right  angles  to  each  other,  so  that 
the  dead  centre  of  one  corresponds  to  the  active 
period  of  the  other.  The  poles  of  the  electro- 
magnets are  joined  at  each  side  by  a  brass 
framework,  which  extends  outward,  and  has 
bearings  on  which  the  shaft  turns,  as  will 
be  readily  understood  from  the  figures.  The 


toothed  wheel  which  revolves  at  one-tenth  the 
speed  of  the  pinion. 

By  changing  the  connections  of  the  electro- 
magnets and  armatures  from  series  to  multiple, 
three  different  variations  of  power  may  be  ob- 
tained. The  change  may  be  made  without 
trouble.  The  motor  is  very  compact  and  light. 
It  has  no  dead  centre  and  the  magnets  are  dis- 
posed so  as  to  secure  a  powerful  magnetic  field, 
which  must,  of  necessity,  be  exactly  equal  at 
both  armatures. 

The  electric  motor  of  M.  Esteve  (Fig.  113) 
brought  before  the  public  in  France  contempo- 
raneously with  that  of  Deprez,  possesses  origi- 


INDUSTRIAL  APPLICATION  OF  ELECTRIC   MOTORS  IN  EUROPE. 


117 


nal  features  of  great  interest.  In  this  motor  the 
ordinary  H  Siemens  armature  is  materially 
modified  in  form,  and  the  magnetic  field  in 
which  it  rotates  is  also  different.  In  all  other 
small  electric  motors  of  this  old  Siemens  type 
the  original  H  form  of  armature  has  always 
been  adhered  to  with  magnetic  field  pieces  of 
varied  form.  M.  Deprez  preferred  in  his  earlier 


FIG.  113. — ESTEVK  MOTOR. 

forms  to  give  to  the  armature  poles  A  B  a  consid- 
erable expansion,  and  to  restrict  the  field  pieces 
in  size,  so  that  they  do  not  surround  the  arma- 
ture so  completely.  This  is  the  disposition 
adopted  in  his  motor  just  described,  the  rela- 
tive proportion  of  armature  and  field-pole  ex- 
pansions being  indicated  by  the  section  shown 
in  Fig.  114. 

In  his  motor  M.  Esteve  evidently  follows  a 
different  theory,  as  the  magnetic  field  is  ex- 
panded so  as  to  surround  the  armature  as 
completely  as  in  ordinary  dynamo-electric 
machines,  while  the  polar  expansions  of  the 
armature  are  entirely  suppressed,  and  it  as- 
sumes the  sectional  appearance  of  the  letter  /, 
as  shown  in  Fig.  114,  which  is  a  sectional  plan 
of  this  armature  and  its  magnetic  field.  The 
armature  is,  in  fact,  made  of  a  flat  plate  of  iron 
revolving  on  its  longer  axis,  as  if  the  polar  ex- 
pansions of  the  H  armature  had  been  filed 
down  to  a  level  with  the  central  part.  The  dif- 
ference will  be  readily  understood  on  com- 
paring Figs.  110  and  114. 

Better  results  are  obtained  when  the  armature 
core  is  made  up  of  layers  of  thin  sheet  iron 
separated  from  each  other  by  means  of  paper, 
but  M.  Esteve  prefers  to  make  the  core  with  a 
hollow  centre,  using  insulated  plates,  which 

15 


must  be  sufficiently  thick,  otherwise  the  mag- 
netic reaction  of  the  armature  on  the  magnetic 
field  is  lessened  materially,  just  as  when  no  iron 
cores  are  used,  and  the  efficiency  of  the  motor 
is  considerably  reduced.  M.  Esteve  has  also 
tried  the  use  of  armature  cores  constructed  of 
insulated  iron  wire,  but  the  efficiency  obtained 
was  not  greater  than  with  the  hollow  armature 
just  mentioned.  He  finds  that  the  coercive 
force  of  this  hollow  armature  is  extremely 
small,  consequently  that  the  polarity  may  be 
reversed  with  extreme  rapidity. 

The  construction  of  this  motor  is  quite  simple 
and  will  be  readily  understood  from  Fig.  113. 
The  cores  of  the  field  magnet  are  made  of  cast 
iron  forming  one  piece  with  the  base,  though 
the  winding  is  more  convenient  when  they  are 
cast  separate.  The  wire  is  wound  on  the  arma- 
ture in  two  equal  sections  C  C'  D  D  (Fig.  114), 
leaving  a  small  space  E  E'  between  them. 
These  sections  may  be  connected  either  in 
series  or  in  multiple  circuit,  according  to  cir- 
cumstances. The  ends  go  to  the  two  commuta- 
tor segments  C,  which  M.  Esteve  prefers  to  make 
of  iron.  This  is  a  new  departure,  because  the 
use  of  copper  in  commutators  has  always  been 
regarded  as  well-nigh  indispensable.  M.  Esteve 
says,  in  favor  of  iron  commutators,  that  they 
wear  out  much  less  and  do  not  spark  as  much 
as  copper  ones,  while  their  resistance  of  con- 
tact is  not  sensibly  different.  At  any  rate,  he 
does  not  find  any  loss  in  efficiency  in  conse- 
quence of  using  them.  The  brushes  F  F  are 
both  held  by  an  oscillating  lever,  which  can  be 


FIG.  114. 

secured  at  any  convenient  angle  by  the  set 
screw  V,  the  arrangement  being  particularly 
useful  in  permitting  the  adjustment  of  the 
brushes  to  the  point  of  least  sparking. 

The  field  magnet  and  the  armature  are  con- 
nected in  series,  and  in  this  condition  there  is 
little  or  no  sparking  at  the  brushes,  even  when 
using  powerful  currents.  M.  Esteve  experi- 
mented with  one  of  his  motors  placed  in  a 
branch  circuit  from  a  Gramme  machine,  and 


118 


THE   ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


found  that  its  operation  was  entirely  satisfac- 
tory, the  motor  remaining  cool  and  free  from 
sparks  at  the  commutator.  Experiments  have 
also  been  tried  with  this  motor  when  its  field 
circuit  was  derived  from  the  armature  circuit, 
as  in  "shunt"  dynamos,  but  the  results  were 
not  as  satisfactory. 

It  is  plain  that  when  constructed  in  this  form, 
the  motor  is  open  to  the  objection  of  having  a 
dead  centre,  but  M.  Esteve  suggests  that  by 
making  the  magnetic  field  somewhat  wider, 
two  or  three  armatures  may  be  placed  on  the 
same  shaft,  just  as  in  the  Deprez  motors. 

The  design  of  this  little  motor  both  electric- 
ally and  mechanically  is  very  good,  con- 
sidering the  limitations  which  convenience, 
cheapness,  and  durability  impose.  The  form  of 
armature  appears  to  be  an  improvement  in  the 
right  direction.  It  has  been  shown  by  M. 
Trouve*  that  with  the  ordinary  Siemens  H  arma- 
ture the  magnetic  attraction  which  causes  the 
rotation  is  not  effective  for  more  than  a  small 
portion  of  the  revolution.  A  little  reflection 
will  make  this  clear.  In  a  motor  of  this  type 
we  have  practically  two  magnets,  one  of  which 
tends  to  move  constantly  so  as  to  place  itself 
axially  in  the  magnetic  field  of  the  other  with 
like  poles  near  each  other.  If  the  poles  of  the 
moving  magnet  are  broad  and  expanded  it  does 
not  require  to  move  so  much  before  a  certain 
part  of  the  pole  arrives  at  the  axial  position. 
The  magnetic  attraction  becomes  concentrated 
at  these  points,  and  there  is  little  or  no  ten- 
dency to  the  further  motion  of  the  armature  so 
as  to  bring  the  rest  of  its  mass  into  the  axial 
magnetic  position.  The  result  is  that  the 
rotative  impulse  ceases  at  a  certain  distance  be- 
fore the  armature  reaches  the  axial  position 
shown  in  the  figure,  and  the  armature  must  de- 
pend on  its  momentum  to  carry  it  as  far  as  the 
point  where  the  current  is  reversed  and  where 
repulsion  will  begin.  M.  Trouve,  in  his  motors, 
sought  to  remedy  this  difficulty  in  two  ways: 
First  by  making  the  face  of  the  polar  expansion 
of  the  armature  curve  on  a  shorter  radius,  and 
second  by  making  the  field  more  open  at  cer- 
tain points,  or  elliptical  in  shape.  The  object  in 
either  case  was  to  provide  for  a  more  gradual 
approach  between  the  pole  of  the  armature  and 
the  iron  of  the  magnetic  field  poles,  so  that  the 
motion  would  not  cease  until  the  whole  mass  of 
the  armature  was  in  the  magnetic  axis.  By 
these  means  the  efficiency  of  the  motor  was 


greatly  increased  and  the  dead  centre,  which 
before  that  comprised  a  certain  period  of  the 
rotation,  was  now  reduced  to  a  mere  point. 

In  the  motor  of  M.  Esteve  the  armature 
necessarily  attains  the  object  more  readily  and 
surely.  It  is  more  certain  to  reach  the  position 
shown  in  the  figure,  because  no  portion  of  it 
reaches  the  axial  position  sooner  than  the  rest. 
However,  the  magnetic  attraction  must  un- 
doubtedly become  partially  satisfied  as  soon  as 
the  poles  A  B  (Fig.  110)  approach  the  magnetic 
field  pole,  and  this  must  tend  to  weaken  the 
rotative  impulse.  By  making  the  field  elliptical 
the  approach  would  be  still  more  gradual,  and 
the  result  would  be  a  more  equable  rotative 
impulse.  The  conchoidal  field  of  M.  Trouve" 
may  also  be  recommended.  An  idea  of  this 
form  of  field  will  be  obtained  by  supposing  the 
field  piece  N  (Fig.  114)  to  be  depressed  so  that 
the  upper  edge  of  the  pole  is  nearest  to  the 
armature  and  the  lower  edge  most  distant  from 
the  armature,  while  the  pole  S  is  elevated  so 
that  its  lower  edge  is  nearest  and  its  upper  the 
furthest  from  the  armature. 

The  field  magnet,  of  which  the  iron  base 
forms  a  part,  is  comparatively  massive,  and  its 
point  of  magnetic  saturation  is  not  so  soon 
reached  as  when  there  is  less  iron.  This  is  an 
important  quality,  especially  when  the  motor  is 
worked  to  its  highest  capacity,  as  well  as  when 
the  motor  is  used  as  a  generator  of  current. 
When  once  the  point  of  saturation  is  reached, 
then  it  avails  nothing  to  increase  the  strength 
(magnetizing  power)  of  the  current,  because 
the  iron  cores  are  "  full,"  and  will  not  receive 
any  more  magnetism.  Any  current  beyond  the 
amount  necessary  to  produce  saturation  is 
wasted.  Another  argument  in  favor  of  a  good 
mass  of  iron  is  that  the  nearer  the  point  of 
saturation  a  magnetic  metal  is,  the  more  cur- 
rent is  required  to  cause  a  proportional  increase 
in  magnetism.  When  there  is  plenty  of  iron, 
the  "  margin  "  between  the  non-magnetized  and 
the  saturation  point  is  wider. 

One  of  the  most  indefatigable  and  successful 
inventors  of  electric  motors  has  been  Mr.  An- 
thony Reckenzaun,  C.  E.,  of  London.  The  ac- 
companying illustration  (Fig.  115)  is  a  per- 
spective view  of  his  motor  made  in  1884,  and 
exhibited  at  the  International  Electrical  Ex- 
hibition at  Philadelphia  that  year,  by  Mr.  Fred. 
Reckenzaun,  brother  of  the  inventor.  The 
magnets  are,  in  appearance.,  somewhat  similar 


INDUSTRIAL  APPLICATION  OF  ELECTRIC   MOTORS   IN  EUROPE. 


119 


to  those  employed  in  the  Siemens  dynamo,  ex- 
cept that,  as  will  be  seen  from  the  cut,  the 
cores  are  in  an  inclined  position,  the  upper 
and  lower  core-ends  meeting  at  a  rather  acute 
angle.  This  arrangement  saves  space,  reduces 
the  weight,  and  renders  the  frame  rigid.  The 
armature  consists  of  a  ring,  made  up  of  a  series 
of  rings,  each  of  which  is  again  composed  of  a 
number  of  links  provided  with  holes  at  their 
ends  to  receive  the  bolts  which  hold  the  links  as 
well  as  the  rings  together.  The  links,  overlap- 


shaft  inside  the  armature.  These  inside  collars 
are  in  metallic  connection  with  a  pair  of  similar 
collars  at  the  commutator,  where  another  pair 
of  brushes  rests  on  them,  picking  up  a  small 
current  for  the  internal  magnet.  This  internal 
circuit  forms  a  shunt  to  the  main  circuit. 
The  internal  magnet,  on  being  excited,  offers 
two  poles,  each  facing  a  like-named  external 
field-magnet  pole.  Hence  the  passing  arma- 
ture bobbins  are  exposed  to  strongly  magnet- 
ized pole  pieces  inside  as  well  as  outside, 


FIG.  115. — RECKENZAUN  MOTOR. 


ping  one  another,  are  insulated  from  each 
other  in  order  to  avoid  Foucault  currents. 
From  twelve  to  thirty-six  bobbins  surround  the 
ring  thus  formed  and  connect  with  a  com- 
mutator made  up  of  a  corresponding  number  of 
sections.  A  pair  of  brush-holders  carry  two 
brushes,  movable  within  a  certain  range  to  ad- 
just the  speed  of  the  motor.  Inside  the  arma- 
ture is  a  magnet,  resting  loosely  on  the  shaft 
by  means  of  rollers.  This  internal  magnet  is, 
in  cross-section,  H-shaped.  having  two  pole 
pieces,  between  which  a  quantity  of  fine  wire 
is  wound  lengthwise,  the  ends  of  which  are 
connected  to  copper  brushes  which,  in  running, 
rub  against  two  brass  collars  fitted  upon  the 


thereby  utilizing  also  the  inner  parts  of  the 
wire  bobbins.  The  internal  magnet  is  made 
for  larger  sized  motors,  and  may  be  taken  out 
and  the  motor  run  without  it.  On  top  of  the 
machine  are  two  binding  posts  mounted  on  a 
block  of  wood,  to  which  the  mains  are  con- 
nected. All  the  iron  in  this  motor  is  best 
soft  wrought  iron,  no  cast  iron  being  employed. 
All  parts  are  carefully  proportioned  for  light 
weight,  high  efficiency,  and  strength.  In  case 
the  armature  should  require  repairing,  the  bob- 
bins need  not  be  unwound  as  in  some  other  ma- 
chines, but  any  one  may  be  slipped  off  its  sec- 
tion after  taking  out  the  nearest  bolt,  thus 
saving  time,  labor,  and  material. 


120 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


;-• 

K* 
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H 


C 


1 

«c 


INDUSTRIAL  APPLICATION   OF  ELECTRIC  MOTORS  IN   EUROPE. 


121 


The  motor  exhibited  in  Philadelphia  was  of 
one  and  one-half  actual  horse  power.  It  will 
strike  many  of  our  readers  as  noteworthy 
that  this  motor  weighed  no  more  than  IOC 
pounds,  which  gives  a  co-efficient  of  407,  or, 
in  other  words,  407  foot-pounds  of  work  per 
minute  to  every  pound  of  its  own  weight.  Its 
bulk  was  likewise  exceedingly  small.  The  mo- 
tor measured  in  height  nine  and  one-half  inches, 
width  sixteen  and  one-half  inches,  and  length 
of  shaft  twenty  and  one-half  inches — other 
sizes  in  proportion.  These  facts  have  amply 
justified  its  application  in  England,  not  only 
for  stationary  purposes,  but  also  for  vari- 
ous kinds  of  service  where  light  weight  and 
small  bulk,  combined  with  high  efficiency,  are 
of  great  importance,  such  as  in  connection  with 
electric  launches,  telpher  lines,  mining  work, 
and  other  purposes. 

One  of  the  most  important  departments  of 
mining  operations  is  drilling  and  tunnelling, 
and  naturally,  as  the  beds  and  strata  of  rocks 
and  minerals  near  the  surface  of  the  earth  be- 
come exhausted,  shafts  and  galleries  are  car- 
ried deeper  and  deeper,  with  a  corresponding 
increase  in  the  number  and  extent  of  the  diffi- 
culties that  tend  to  hinder  the  successful  ex- 
ploitation of  rich  deposits.  But,  thanks  to  the 
progress  in  electric  lighting  and  in  the  trans- 
mission of  power,  work  can  be  carried  on  at  a 
greater  depth  below  the  surface  than  ever  be- 
fore, with  a  decrease  of  danger  and  expense. 
Electricity  is  now  applied  to  the  most  varied 
work  in  mines,  and  is  found  equally  available 
in  illuminating  the  galleries  about  which  float 
gases  of  noxious  character,  in  piercing  rocks, 
in  hoisting  and  pumping,  and  in  ventilating; 
and  its  use  enables  the  apparatus  to  be  made  in 
small  and  compact  form,  the  generator  of  cur- 
rent or  prime  source  of  power  being  at  a  dis- 
tance. 

The  accompanying  illustration,  Fig.  110, 
shows  the  Taverdon  drill,  with  Gramme  mo- 
tor, used  in  boring  subterranean  galleries. 
This  invention  is  a  striking  example  of  the 
transmission  of  power  and  the  application  of 
electricity  to  a  new  and  difficult  kind  of  work. 
Numerous  systems  of  rock  drills  have  been  in 
favor  from  time  to  time,  the  apparatus  being 
run  by  steam  or  compressed  air,  but  it  is  as- 
serted on  behalf  of  this  new  plan  or  device  that 
it  is  far  less  cumbersome  aiid  far  more  easy  to 
control  than  any  of  its  predecessors.  M.  Taver- 


don applies  electricity  to  a  rotary  drill,  which 
is  worked  by  a  motor  in  the  manner  indicated. 
In  his  system,  the  drills  carry  at  their  striking 
end  black  diamonds,  capable  of  penetrating  the 
hardest  rocks.  In  order  to  fix  the  diamond 
solidly,  so  as  to  keep  all  its  facets  properly  at 
work,  M.  Taverdon  employs  a  hard  metallic 
solder  that  fills  all  the  cavities.  As  he  could 
not  apply  the  solder  directly  to  the  stone,  he 
first  covers  the  latter  by  electrolysis  with  a  thin 
coating  of  copper.  This  allows  the  application 
of  the  solder,  but  does  not  interfere  at  all  with 
the  parts  of  the  diamond  presented  to  the  rock. 
A  special  carriage  is  provided  both  for  the  per- 
forator and  for  the  motor.  The  perforator  is 
fixed  upon  an  upright  column  adjusted  by  a 
spiral  spring  to  the  roof  and  floor  of  the  gallery 
in  such  a  way  as  to  keep  the  platform  of  the 
car  on  which  it  is  mounted  perfectly  steady. 
It  is  capable  of  movement  on  vertical  and  hori- 
zontal axes,  and  thus  can  be  set  in  any  desired 
position.  The  butt  end  can  be  fitted  with  an 
ingeniously  constructed  motor,  with  a  view  to 
the  use  of  steam,  compressed  air,  or  hydraulic 
pressure,  indifferently,  for  driving,  but  in  the 
electrical  arrangement  a  box  replaces  the  mo- 
tor and  a  simple  pulley  receives  and  turns  with 
the  belt  or  cable  connecting  with  the  electric 
motor  on  the  rear  car.  The  motor  consists  of 
a  Gramme  octagonal  machine,  similar  to  that 
used  in  the  famous  plowing  experiments  atSer- 
maize,  and  its  strong  cast-iron  frame  evidently 
fits  it  for  rough  mining  work.  The  pulley  at 
the  end  of  the  axis  of  the  motor  transmits  the 
power  to  the  box  at  the  end  of  the  drill  by  the 
cable,  which  passes  over  two  other  pulleys  as 
shown,  one  of  the  latter  being  adjustable.  The 
generating  machine  is,  of  course,  outside  the 
gallery  at  any  convenient  distance. 

On  the  car  carrying  the  motor  is  a  water 
tank,  from  which  water  is  forced  to  the  per- 
forator and  is  then  used  to  wash  away  the  sand 
as  quickly  as  it  is  formed  and  accumulates. 
We  ought  to  say  here  that  in  another  drilling 
machine  of  M.  Taverdon,  the  drill  or  boring 
tool  is  fitted  direct  to  the  axis  of  the  motor, 
which  is  driven  in  the  usual  way  and  is  carried 
on  a  car.  This  plan  is  simpler  than  the  other, 
and  apparently  more  economical  of  power,  but 
M.  Taverdon  speaks  highly  of  the  apparatus 
shown  in  the  illustration  and  reports  that  from 
it  he  has  obtained  results  equal  to  those  of  the 
best  steam  drills  and  better  than  those  with 


122 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


compressed  air.  The  advantages  of  the  use  of 
electricity  for  this  work  are  easy  to  see.  The 
little  gallery  is  not  cramped  and  choked  up 
with  steam,  air,  or  water  pipes,  which,  besides 
occupying  valuable  space,  are  liable  to  leakage 
and  sometimes  stop  the  work  while  their  de- 


FIG.  117. — LEK-CHASTKR  MOTOR. 

fects  are  being  remedied.  A  noteworthy  feat- 
ure of  the  scene  is  the  use  of  the  incandescent 
lamp;  and  if  necessary  the  blasting  charge  in 
the  drill  holes  can  be  fired  by  an  electric  cur- 
rent. 

A  fair  idea  of  the  extent  to  which  motors  of 
moderate  size  have  already  been  introduced  in 
France,  may  be  formed  from  the  summary  of 
installations  made  up  to  April  1,  1886,  by  the 
Compagnie  Electrique.  This  single  company 
had  effected  forty -two  installations,  using  one 
hundred  and  ninety  Gramme  machines,  with 
a  total  of  310  horse  power.  Of  these  machines, 
thirty -three  are  employed  for  cranes  and  eleva- 
tors, forty  in  driving  machinery  and  tools,  fifty- 
two  with  ventilators,  eleven  in  pumping,  etc., 
and  fifty -four  for  miscellaneous  purposes. 

The  small  motor  illustrated  in  the  engraving, 
Fig.  117,  and  known  in  England  as  the  Lee- 
Chaster,  was  lately  introduced  to  public  notice. 
It  occupies  a  space  of  8  in.  by  8  in.,  and  is  said 
to  be  capable  of  developing  energy  equal  to 
nearly  three-fourths  horse  power,  and  can  be 
started,  stopped,  or  reversed  by  the  simple 
movement  of  a  switch.  It  is  driven  by  a  bat- 
tery, which  is  said  to  involve  the  minimum  of 
trouble,  which  will  run  for  about  twenty  hours 


without  recharging,  and  can  then  be  restarted 
with  fresh  solution  in  a  very  short  time.  The 
cells  are  charged  with  Lee's  new  double  bichro- 
mate, soluble  in  its  own  weight  of  cold  water, 
and  which  does  not  deposit  crystals  in  the  pores 
of  the  carbons  or  in  the  cells.  Moulded  corru- 
gated carbons  are  used,  and  the  zincs  are  so  cut 
as  to  economize  the  metal.  The  cells  rest  on  a 
tray  in  a  box,  and  the  tray  can  be  raised  by 
means  of  a  treadle  until  the  elements  are  fully 
immersed  in  the  solution.  Both  zincs  and  car- 
bons are  suspended  from  a  board,  which  forms 
a  lid,  so  to  speak,  and  the  connections  are  made 
by  means  of  brass  plates,  thus  avoiding  the  use 
of  wires.  Two  wing  nuts  hold  this  board  to 
the  mechanism  of  levers,  and  by  removing 
them,  the  whole  battery  of  elements  can  be 
lifted  out,  leaving  the  cells  exposed.  The  zincs 
and  carbons  are  automatically  removed  from 
the  solutions  when  the  treadle  is  released,  and 
the  amount  of  immersion  can  be  regulated  to  a 
nicety. 

Professors  Ayrton  and  Perry  have  devoted 
much  attention  to  the  study  of  electric  motors, 
and  as  a  result  they  have  promulgated  the  the- 
ory,— which  we  have  already  drawn  attention 
to  in  a  preceding  chapter, — that  whereas  in  the 
dynamo  the  field  should  be  of  great  magnetic 
strength  and  the  armature  a  weak  one  magnet- 
ically, the  reverse  should  be  observed  in  the  mo- 


FlG.    118. — AVRTON-I'ERRY   MOTOR.  * 

tor;  i.  e. ,  the  field  should  be  a  weak  magnet  and 
the  armature  a  powerful  magnet.  They  have 
embodied  their  ideas  in  a  form  of  motor  which 
differs  from  those  of  ordinary  construction  in 
that  the  armature  is  kept  stationary  while  the 
field  magnet  revolves  within  it. 

Fig.  118  shows  the  Ayrton-Perry  motor  in 
perspective;  Fig.  119  shows  the  construction  of 
the  motor  more  in  detail.  The  stationary  arma- 


INDUSTRIAL  APPLICATION  OP  ELECTRIC  MOTORS  IN  EUROPE. 


123 


ture,  as  will  be  seen,  consists  of  a  laminated 
cylinder  built  up  of  toothed  rings  of  sheet  iron, 
and  resembles  very  much  the  Pacinotti  toothed 
ring  armature.  The  wires  are  wound  on  in 
sections,  joined  in  series,  and  at  each  joint  are 


istic  parabolic  contour  of  revolving  liquids  en- 
closed in  vessels,  and  at  a  certain  speed  the 
wire  would  be  left  out  of  contact  with  the  mer- 
cury. The  circuit  would  then  be  broken,  the 
current  cease,  and  the  speed  of  the  motor  would 
fall  again.  The  great  objection  to  this  form  of 
governor  is  that  it  either  supplies  full  power 
when  the  motor  is  running  too  slowly,  or  no 
power  when  the  motor  is  running  too  fast,  and 
hence  is  incapable  of  maintaining  .  constant 
speed. 


FIG.  119.— DETAILS  OF  AYRTON-PEHRY  MOTOR. 

connected  to  a  segment  of  the  stationary  com- 
mutator C  C.  The  spindle  of  the  revolving 
field  magnet  carries  the  brushes  which  revolve 
with  it. 

In  explanation  of  the  operation  of  the  motor, 
Professor  Ayrton  says  that  wherever  the  brushes 
B  happen  to  be  at  any  particular  moment,  there 
two  opposite  magnetic  poles  at  N  and  S  are  pro- 
duced on  the  armature,  as  shown  in  Fig.  119. 
As  the  brushes  revolve  so  do  these  poles,  and 
the  brushes,  which  are  carried  by  the  field  mag- 
nets, are  so  set  that  the  magnetic  poles  in  the 
armature  are  always  a  little  in  front  of  those  in 
the  field  magnet.  The  latter,  therefore,  are,  as 
it  were,  perpetually  running  after  the  former, 
but  never  catching  them. 

Professors  Ayrton  and  Perry  have  also  devoted 
considerable  attention  to  the  regulation  or  gov- 
erning of  electric  motors,  and  have  devised  sev- 
eral methods  of  accomplishing  this  result.  One 
of  their  oldest  forms,  known  as  their  "  spas- 
modic governor,"  consisted  of  a  trough  of  mer- 
cury, which  revolved  with  the  field  magnet, 
and  had  a  wire  dipping  into  the  mercury  through 
which  the  current  passed.  As  the  speed  in- 
creased, the  mercury  would  take  the  character- 


FIG.  120. — REGULATOR  OF  AYRTON-PERRY  MOTOR. 

Professors  Ayrton  and  Perry  have,  however, 
designed  several  other  forms  and  experimented 
with  other  and  more  perfect  methods  of  govern- 
ing electric  motors,  one  among  them  consisting 
in  winding  the  motor  with  two  distinct  circuits 


124 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


in  such  a  way  that  the  current  passing  through 
one  of  them  magnetizes  the  iron,  causes  the 
machine  to  act  as  a  motor,  and  consequently 


FIG.  121. — REGULATOR  OF  AYIITOX-PF.RRY  MOTOR. 

is  itself  resisted,  whereas  the  current  passing 
through  the  other  circuit  tends  to  demagnetize 
the  iron  and  stop  the  motion.  This  evidently  is 


equivalent  to  a  differential  winding  and  does 
away  with  all  mechanical  governing. 

Where  it  is  required  to  change  frequently  the 
speed  and  direction  of  rotation  of  an  electric 
motor,  such  as  upon  a  tram-car,  Professors  Ayr- 
ton  and  Perry  have  applied  the  method  of 
varying  the  lead  of  the  hrushes.  Figs.  120  and 
121  illustrate  the  manner  in  which  this  is  ac- 
complished. By  pushing  the  handle  fully  for- 
ward the  motor  revolves  rapidly  in  one  direc- 
tion; when  pulled  back  in  the  other  direction 
the  motor  reverses.  At  intermediate  position 
corresponding  lower  speeds  are  obtained.  The 
action  of  this  lead  adjuster  is  as  follows: 

Attached  to  the  rotating  field  magnet  is  the 
spindle  S  S,  which  is  itself  attached  to  and  ro- 
tates with  the  outer  collar  C  C.  On  pushing 
the  handle  forward  or  backward,  this  collar 
is  moved  along  the  spindle,  and  the  effect  of 
this  is  to  cause  a  pin  to  move  along  the  groove 
G  O  and  so  cause  the  inner  collar  P  P,  which 
usually  rotates  along  with  C  C  and  the  field 
magnet,  to  move  a  little  forward  or  backward 
relatively  to  C  C.  Since  the  collar  P  P  is 
screwed  to  the  brush-holder,  it  is  possible,  even 
when  the  motor  is  running,  to  shift  the  brushes 
relatively  to  the  field  magnet  together  with 
which  they  are  rotating,  and  consequently  with 
only  one  pair  of  brushes  to  give  any  desired 
lead  forward  or  backward.  In  other  cases  the 
lead  is  altered  by  means  of  a  wheel  and  screw 
which  permits  of  very  accurate  adjustment. 

From  the  peculiar  construction  of  the  Ayrton 
and  Perry  motor,  it  may  be  operated  without 
any  wire  at  all  upon  the  revolving  field  mag- 
nets. This  arises  from  the  fact  that  the  mag- 
netism in  the  stationary  armature  induces 
opposite  magnetism  in  the  iron  of  the  field 
magnets,  and,  as  pointed  out  before,  the  brushes 
are  so  placed  that  the  magnetic  poles  in  the 
armature  are  always  just  in  front  of  those  in 
the  iron,  which  latter  are  always  running  round 
after  those  in  the  former  but  never  catch  up 
with  them. 


CHAPTER   IX. 


THE   INDUSTRIAL  APPLICATION  OK  ELECTRIC  MOTORS   IN 

AMERICA. 


THERE  are,  as  the  previous  chapter  exempli- 
fies, a  thousand  and  one  places  to-day  where 
small  electric  motors  are  greatly  needed  and 
can  be  used.  In  large  cities,  and  manufactur- 
ing towns  of  any  importance,  where  hundreds 
of  small  steam  engines  have  been  in  use,  each 
requiring  to  be  fired  and  attended,  the  electric 
motor  is  of  the  greatest  utility,  its  chief  features 
of  recommendation  being  that  it  generates  no 
heat,  smoke,  or  smell,  requires  scarcely  any 
care  the  year  round,  can  be  entrusted  to  un- 
skilled hands,  makes  little  noise,  is  ready  to 
start  or  stop  at  a  turn  of  the  switch,  keeps  up  a 
steady  motion,  is  under  perfect  control,  and 
where  a  central  power  or  lighting  station  ex- 
ists, is  cheap  to  operate.  The  success  that  has 
attended  the  central  power  stations  already  in 
existence  in  America  attests  the  appreciation 
in  which  such  a  convenient  source  of  supply  is 
held,  and  the  record  is  made  almost  daily  of 
new  installations.  There  can  be  no  doubt  that 
as  regards  convenience  and  applicability,  elec- 
tric transmission  of  power,  for  the  reasons 
above  given,  stands  without  rival.  It  is  often 
the  case,  too,  that  power  users  crowd  into 
buildings  where  they  pay  high  rents,  solely  be- 
cause in  other  places  they  cannot  get,  or  are 
not  allowed  to  use,  steam  or  gas.  The  electric 
motor  is  highly  economic  of  space,  and  the 
wires  leading  to  it  can  be  run  out  of  sight, 
through  the  smallest  cracks  and  holes,  around 
corners  of  the  sharpest  angle,  and  to  heights  or 
depths  at  which  no  one  dreams  of  placing  or- 
dinary power-generating  machinery. 

We  have  already  spoken  briefly  of  the  work 
now  being  done  in  Europe,  industrially  and 
otherwise,  by  small  motors.  The  application 
has  not  been  neglected  in  America.  One  of  the 
most  successful  of  recent  inventors  has  been 
Mr.  Griscom,  of  the  Electro-Dynamic  Company, 
of  Philadelphia,  whose  motor  during  the  last 
four  or  five  years  has  come  into  very  extensive 

16 


application,  not  only  here,  but  in  England  as 
well.  Its  principal  excellence  is  to  be  found  in 
the  neat  and  compact  design  given  to  it — a  feat- 
ure which  recommends  it  to  many  uses  where 
other  machines  would  be  rejected,  especially  in 
domestic  work.  The  motor  is  of  the  same  type 
as  the  Deprez  and  Trouve  motors,  inasmuch  as 
its  armature  is  of  the  old  Siemens  form;  but  the 
magnetic  field  in  which  the  armature  revolves 
is  entirely  different  in  shape.  The  motor  has 
received  the  name  of  "double  induction  mo- 
tor," from  a  peculiar  phenomenon  which  was 
noticed  by  its  inventor  while  experimenting 
with  it.  Ordinarily,  the  armature  is  included 
in  the  same  circuit  as  the  coils  on  the  field  mag- 
nets. Mr.  Griscom  once  happened  to  pass  a 
current  through  the  armature  circuit  alone,  the 
field  circuit  being  disconnected.  In  this  condi- 
tion the  armature,  being  powerfully  magnet- 
ized, acted  on  the  iron  of  the  field  magnets  and 
tended  to  move  so  as  to  bring  its  poles  in  a  line 
with  the  poles  of  the  field  magnet,  and  there, 
the  magnetism  of  the  armature  being  reversed, 
a  mutually  repulsive  effect  between  this  pole 
and  the  residual  magnetism  of  the  field  mag- 
nets arose  and  tended  to  cause  the  armature  to 
move  away  toward  the  other  poles,  so  that  once 
started  the  armature  would  continue  to  turn 
somewhat  slowly.  It  was  found,  however,  that 
if  the  field  circuit,  while  still  detached  from  the 
battery  circuit,  was  simply  short-circuited  upon 
itself,  the  motor  would  begin  to  revolve  very 
rapidly.  Mr.  Griscom  concluded  that  by  the 
motion  of  the  armature  its  lines  of  force  are 
cut  by  the  field-magnet  coils,  and  thus  give  rise 
to  a  current  in  the  latter  which  helps  to  mag- 
netize the  field,  and  he  ascribed  the  phenom- 
enon to  the  peculiar  conformation  of  the  field 
magnet,  which  is  such  as  to  bring  its  wire  close 
to  the  revolving  armature.  This  phenomenon 
attracted  much  attention  and  caused  considera- 
ble discussion,  especially  in  Europe. 


126 


THE   ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


One  sufficient  theory,  as  opposed  to  the  above, 
is  that  the  closed  circuit  simply  prevents  the 
induced  magnetism  from  diminishing  on  ac- 
count of  the  "Lenz  effects"  which  arise  in  the 
closed  circuit,  and  that  as  the  magnetism  is 
slightly  increased  at  each  turn  by  the  induction 
of  the  armature,  the  magnetic  intensity  of  the 
field  soon  reaches  a  maximum.  Whatever  in- 
duction is  produced  by  the  lines  of  force  of  the 
armature  must  necessarily  be  of  a  nature  to 
oppose  the  motion  instead  of  helping  it.  This 
inference  is  indeed  a  valid  consequence  of 
Lenz's  law.  When  the  field  magnet  is  in  the 
same  circuit  as  the  armature,  and  fed  from  a 
battery  current,  the  phenomenon  does  not  oc- 


FIG.  122. — THE  GRISCOM  MOTOR. 

cur  after  the  magnets  have  reached  saturation, 
which  takes  place  almost  instantly;  so  that  the 
term  "  double  induction  "  is  a  misnomer.  How- 
ever, the  motor  can  sustain  its  reputation  quite 
well,  even  without  the  supposition  of  double  in- 
duction, for  it  certainly  attains  a  remarkable 
efficiency.  It  is  saidthatitcanlift2,000times  its 
weight  (forty  ounces)  in  one  minute,  when  work- 
ing with  the  full  battery  power.  This  gives  it 
a  capacity  of  nearly  one-sixth  of  a  horse-power. 
The  motor  is  remarkable  for  the  small  space 
it  occupies,  due  to  its  neat  and  compact  design, 
shown  in  Fig.  122,  which  is  nearly  full  size. 
The  armature  is  entirely  encased  by  the  cylin- 
drical electro-magnet  within  which  it  revolves, 
and  by  the  metallic  caps  or  discs  fitted  to  this 
cylinder  at  each  end.  The  cylindrical  field 
magnet  is  composed  of  a  cylinder  of  soft  iron 
wired  in  two  large  coils,  each  of  which  covers 
nearly  one-half  of  the  cylinder,  the  space  left 


between  the  two  coils  at  opposite  sides  of  the 
cylinder  constituting  the  magnetic  poles  of  this 
cylindrical  electro-magnet.  The  current  which 
passes  through  the  wire  on  this  magnet  circu- 
lates in  opposite  directions  in  each  coil  or  sec- 
tion, so  that  both  coils  combine  -to  produce  a 
north  pole  in  one  of  the  open  spaces  and  a  south 
pole  at  the  other.  The  result  is  practically  the 
same  as  if  two  U  electro-magnets  were  brought 
together  with  like  poles  in  opposition,  these 
forming  a  circular  magnet  with  two  consequent 
or  combined  poles,  one  at  each  junction.  The 
iron  of  the  cylindrical  magnet  projects  laterally 
at  each  pole,  and  to  these  projections  an  orna- 
mental brass  disc  is  screwed  firmly  at  one  end, 
as  shown  in  the  figure.  This  disc  forms  one  of 
the  bearings  of  the  armature  shaft,  which 
passes  through  it,  and  at  the  same  time  serves 
to  protect  the  armature  from  injury.  At  the 
other  end  of  the  motor  another  brass  plate  is 
similarly  fastened  to  the  lateral  projections  of 
the  poles  of  the  cylindrical  magnet.  The  shaft 
of  the  armature  has  a  bearing  in  this  plate  also. 
The  binding  posts  which  receive  the  current 
from  the  battery  pass  through  this  plate.  In 
the  figure  one  is  shown  at  the  top  and  the  other 
a  little  to  the  side  of  it.  The  binding  post 
shown  at  the  top  is  prolonged  on  the  other  side 
of  the  metallic  cap,  and  carries  one  of  the  brass 
springs  or  brushes  which  serve  to  convey  the 
current  to  the  armature  by  pressing  on  the 
commutator.  The  other  brush,  touching  on 
the  opposite  side  of  the  commutator,  is  held 
in  place  by  a  special  screw  device  attached 
to  the  metallic  cap.  The  armature  and  the 
field  magnet  are  connected  in  series,  as  may 
be  readily  seen  from  the  figure.  The  current, 
entering  the  armature  by  the  upper  commuta- 
tor spring,  leaves  it  by  the  lower,  from  which 
it  passes  to  the  field  magnet,  whence  it  goes 
to  the  second  binding  post. 

The  Griscom  motor  weighs  only  forty  ounces, 
and,  as  said  above,  can  develop  a  power  of 
5,000  foot-pounds  per  minute  (that  is,  nearly 
one-sixth  of  a  horse  power)  without  difficulty. 
It  has  been  in  great  demand  for  working  sewing 
machines,  and  is  also  being  used  very  exten- 
sively for  many  other  industrial  purposes.  It 
has  proved  of  great  utility  and  convenience  to 
surgeons,  and  especially  to  dentists,  in  driving 
various  surgical  instruments.  The  well  known 
dental  engines  used  for  rotating  the  excavating 
drills  used  to  remove  the  decayed  portions  of 


INDUSTRIAL  APPLICATION  OF  ELECTRIC   MOTORS   IN  AMERICA. 


127 


teeth  are  all  operated  by  a  treadle,  which  not 
only  obliges  the  operator  to  remain  in  fatiguing 
positions  for  several  hours,  but  requires  him  to 
keep  up  a  monotonous  and  tiresome  movement. 
By  a  clever  adaptation  of  the  electro-dynamic 
motor  to  the  flexible  shaft  of  a  dental  engine, 
these  disadvantages  are  obviated.  The  appara- 
tus is  suspended  either  by  balanced  cords  from 
the  ceiling,  or  from  an  adjustable  arm,  which 
allows  it  to  remain  balanced  at  any  height  or 
desired  angle,  thus  relieving  the  operator  of  the 
weight  of  the  apparatus  and  permitting  him  to 
manipulate  the  drills  as  delicately  as  a  pen. 


nets  are  divided  so  that  there  are  two  or  more 
circuits  around  the  core.  By  suitable  devices 
these  are  so  related  that  they  can  be  thrown 
into  series  or  into  multiple  arc,  or  into  other 
combinations  when  there  are  more  than  two  cir- 
cuits, for  the  purpose  of  changing  the  strength 
of  the  magnetic  field,  to  suit  the  electromotive 
force  and  strength  of  current  supplied  to  the 
motors. 

The  armatures  are  modelled  in  principle  after 
the  Gramme,  but  their  construction  is  much  im- 
proved, especially  in  respect  to  the  manner  of 
mounting  them  on  their  shafts.  Instead  of 


FIG.  123. — DAFT  GENERATOR  OF  1884. 


New  forms  of  the  Griscom  motor  are,  we  un- 
derstand, now  being  designed  and  constructed 
for  more  general  use. 

To  this  department  of  electricity,  as  well  as 
to  the  use  of  motors  on  railways  and  street-car 
lines,  Mr.  Leo  Daft  has  paid  considerable  atten- 
tion. We  illustrate  here  some  of  the  machines 
made  by  him  in  1884,— it  being  unnecessary  to 
go  further  back.  Fig.  123  shows  a  typical  Daft 
generator,  already  referred  to  in  the  preceding 
chapter  on  American  electric  railways,  and  Fig. 
125  a  motor.  The  field  magnets  are  made  after 
what  is  called  the  Siemens  plan.  That  is,  they 
lie  horizontally,  have  consequent  poles,  one 
above  and  the  other  below  the  armature.  They 
are  series  wound,  but  the  coils  of  the  field  mag- 


wood,  suitably  insulated  metallic  spiders  and 
connections  are  used  for  the  purpose.  Thus 
there  is  left  a  space  within,  around  the  shaft, 
through  which  air  can  circulate  for  ventilating 
and  cooling  purposes. 

As  high  speed  is  favorable  to  the  efficiency  of 
electric  motors,  they  are  provided  with  gearing 
so  that  the  armatures  may  be  run  at  high 
speed,  but  communicate  to  the  driving  pulley 
only  a  moderate  rapidity  of  rotation.  With 
that  end  in  view,  the  armature  shaft  is  length- 
ened on  the  end  opposite  the  collector;  two 
bearings  are  there  provided,  and  between  them 
there  is  a  steel  worm  gearing  with  a  phosphor- 
bronze  wheel  on  the  shaft  carrying  the  driving 
pulley.  This  makes  a  good  wearing  combina- 


128 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


FK;.  121.— XKW  DAFT  GKNEUATOR. 


FIG.  125.— DAFT  Morou  WITH  GKAKI.NO. 


INDUSTRIAL  APPLICATION  OF   ELECTRIC   MOTORS  IN  AMERICA. 


129 


tion.  The  bearings  of  the  armature  shaft  are 
of  phosphor-bronze,  and  an  end  plate  and  ad- 
justing screw  are  provided  to  receive  the  thrust 
of  the  shaft  due  to  the  gearing.  The  whole 
makes  a  very  practicable  combination,  taken  in 
connection  with  the  means  of  varying  the  field 
strength  of  the  magnets  of  both  generator  and 
motor. 

Two  of  the  motors  have  been  in  use  in  Spruce 
street,  New  York  city,  one  since  January,  1884, 
and  the  other  since  April,  1884, 
giving  great  satisfaction  in  the 
operation  of  freight  elevators 
which  have  a  capacity  of  2,000 
pounds  with  a  speed  of  from 
thirty  to  thirty-five  feet  a  min- 
ute. One  of  them  was  also  put 
to  work  as  long  ago  as  1883, 
in  the  steam  mills,  Newburgh, 
N.  Y.,  to  operate  an  elevator 
raising  a  load  of  1.800  pounds. 
The  New  York  elevator  motors 
run  continually  during  working 
hours.  When  not  engaged  in 
raising  the  elevators  they  run 
faster  than  when  doing  work. 
Consequently  their  counter-elec- 
tromotive force  cuts  down  the 
current  supplied  to  them  to  the 
point  of  supplying  the  energy 
necessary  to  overcome  the  fric- 
tion of  the  motors  and  their 
gearing.  The  average  speed 
when  at  work  is  1,200  revolu- 
tions per  minute.  The  differ- 
ence of  potential  at  the  binding 
posts  is  about  ninety  volts.  The 
current  varies  with  the  load,  but 
averages  about  twenty-five  amperes  to  each 
machine.  The  actual  power  recovered  is  said 
to  be  sixty-six  per  centum. 

The  armature  of  the  generator  has  a  resist- 
ance of  0.23  ohm.  Its  speed  is  1,100  turns  per 
minute.  Its  electromotive  force  is  ninety  volts, 
and  its  extreme  practical  current  capacity 
seventy  amperes.  Hence  it  can  deliver  6,300 
voltamperes  of  electrical  energy,  or  •yyV  = 
8.44  horse  power.  Fig.  124  shows  the  latest  type 
of  Daft  generator. 

With  a  Daft  motor  of  this  type,  and  of  one 
and  one-half  horse  power,  The  Electrical  World 
gave  an  interesting  exhibition  of  printing  by 
electricity  at  the  International  Electrical  Exhi- 


bition in  Philadelphia,  September  and  October, 
1884.  For  six  weeks,  the  regular  and  special 
editions  of  the  paper  were  printed  from  electro- 
types on  a  31x40  Cottrell  press  made  specially 
by  Messrs.  C.  B.  Cottrell  &  Sons  for  the  occa- 
sion. Although  this  was  not  the  first  time 
printing  by  electricity  had  been  accomplished, 
the  idea  was  quite  new  to  a  great  many  visitors 
to  the  exhibition  and  attracted  unusual  notice. 
The  motor  and  press  worked  without  the  least 


FIG.  126. — DAFT  MOTOR  WITH  BLOWER. 

* 

trouble,  under  the  supervision  of  Mr.  Clarence 
E.  Stump,  the  business  manager  of  the  paper, 
who  had  charge  of  the  exhibit  and  who  found 
the  printing  to  compare  very  favorably  with 
that  done  on  a  press  directly  actuated  by  steam. 
It  may  be  mentioned  here,  as  of  interest,  that 
the  Ilion  (N.  Y.)  Citizen  was  printed  by  a  Par- 
ker motor,  March  14, 1884,  through  a  break-down 
of  its  steam  engine;  and  that  the  Lawrence 
(Mass.)  American  has  been  printed  daily  since 
July  6,  1884,  by  an  electric  motor.  In  a  letter 
written  to  one  of  the  present  authors,  in  Octo- 
ber, 1884,  Mr.  George  S.  Merrill,  proprietor  of 
the  American,  said:  "  We  formerly  used  a  ten 
horse-power  engine,  necessitating  the  employ- 


130 


THE   ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


ment  of  an  engineer,  but  the  employment  of 
the  Edison  Company's  power  gives  a  saving  in 
expense  of  more  than  thirty-three  and  one-third 
per  cent.  The  speed  is  uniform  and  the  power 
satisfactory  in  every  respect."  The  motor  is 
used  to  run  several  cylinder  and  job  presses. 

Fig.  120  shows  a  Daft  motor  attached  to  a  No. 
•i  Sturtevant  blower,  the  two  together  forming 
practically  one  machine.  In  the  blower  illus- 
trated, which  requires  two  horse  power,  three 
speeds  are  obtained,  of  800,  2,000,  and  2,700 
revolutions  per  minute,  by  changing  the  resist- 
ance of  the  field,  thus  doing  away  with  outside 
resistances  and  entailing  no  loss  of  work  due 
to  their  employment. 


FIG.  127. — NEW  DAFT  MOTOR. 

For  some  time  past,  Mr.  Daft  has  devoted  his 
energies  to  meeting  the  requirements  of  the  va- 
rious central  power  stations  established  to  op- 
erate under  his  system.  The  success  experienced 
by  these  power  stations,  especially  in  Boston 
and  Worcester,  Mass.,  has  induced  him  to  enter 
upon  the  manufacture  of  a  more  extended  series 
of  sizes  and  to  remodel  his  machines  to  meet 
the  requirements  of  more  varied  work. 

The  form  which  he  now  employs  is  shown  in 
our  engraving,  Fig.  127.  It  will  be  seen  that 
the  field  magnets  are  of  the  simple  horseshoe 
form,  and  that  the  armature  is  of  the  Gramme 
type,  as  in  Mr.  Daft's  previous  models.  The 
machine  is  designed  to  deliver  normally  six 
horse  power,  but  upon  test  it  has  been  driven 


to  as  high  as  eleven  horse  power  without  inju- 
rious effect. 

Constant  speed  at  all  loads  is  naturally  the 
first  requisite  in  an  electric  motor  designed  for 
stationary  power  plants,  and  hence  accurate 
regulation  must  be  provided  for.  The  present 
machine,  according  to  Mr.  Daft,  maintains  its 
speed  within  two  per  cent.,  between  maximum 
load  and  no  load.  To  obtain  this  result,  the 
machine  has  its  field  wound  compound  with 
three  different  windings.  Of  these  one  is  a 
"  series  "  and  the  other  two  are  shunts. 

The  coils   are  wound    on   spools  which   are 
slipped  over  the  wrought-iron  cores,  and  can 
readily  be  removed  for  examination  when  nec- 
essary.     The    principal    data   re- 
garding the  machine  are  as  fol- 
lows: 

Electromotive  force  de- 
signed for  .         .         .        100  volts. 

Resistance  of  armature,        0.15  ohm. 

"  "  series   coil 

in  field,       .        .        .       .024     " 

Resistance  of  first  shunt 

in  field,        .         .         .     :!2.7'i  ohms. 

Resistance      of      second 

shunt  in  field,     .         .       7.:'>0  ohms. 

Power,   ....  li  h.  j>.  noin. 

Number  of   revolutions 

per  minute,         .         .     ],:>00. 

Weight,          .        .        .        875  ll>s. 

It  is  evident  that  in  a  system  of 
electric  distribution  where  power 
is  furnished  and  sold  to  various 
consumers,  it  is  necessary  to  pro- 
vide some  means  of  controlling 
the  maximum  amount  of  power 
each  customer  may  use,  as  well  as  to  prevent 
injury  to  the  machine  by  unskilled  persons 
starting  it  with  the  full  force  of  the  current  be- 
fore the  inertia  of  the  armature  is  overcome 
and  it  has  attained  speed  enough  to  develop  a 
suitable  working  resistance  or  counter-electro- 
motive force. 

Mr.  Daft  has  provided  for  these  necessities, 
and  places  upon  the  premises  of  each  power 
consumer  an  apparatus  designed  for  this  pur- 
pose. It  is  shown  in  Fig.  128.  Figs.  120  and 
130  are  details  which  are  shown  in  outline  in 
Fig.  128. 

It  will  be  seen  that  mounted  on  a  shaft  sup- 
ported in  journals  is  a  gradually  increasing  cam 
A  of  insulating  material,  and  this  cam  is  ro- 


INDUSTRIAL  APPLICATION  OF  ELECTRIC   MOTORS  IN  AMERICA.  131 


tated  by  a  toothed  wheel  B  on  the  same  shaft, 
and  a  worm  C  meshing  with  the  wheel  and  op- 
erated by  a  crank  from  the  outside.  Upon  the 


so  that  the  operator  may  properly  manipulate 
the  switch  and  know  the  position  of  the  parts 
inside  by  the  location  of  the  indicator  with  ref- 


periphery  of  the  cam  are  arranged  strips  or    erence  to  the  words  "  off  "  and  "  on.' 
sections  D  D  of  copper,  and  supported  in  stand- 
ards and  insulated  from  each  other  are  two  con- 
tact pieces  E  E,  which  bear  upon  the  strips 
on  the  cam.     At  the  highest  part  of  the  cam  is 


FIG.  128. — DAFT  MOTOR — LIMIT  SWITCH. 

placed  a  transverse  conducting  strip  M  insu- 
lated from  the  other  strips  and  adapted  to  com- 
plete the  circuit  direct  between  the  spring 
contacts.  In  the  bottom  of  the  box  is  a  resist- 
ance coil  G  and  a  cut-out  switch  F,  the  ar- 
mature H  of  which  is  ad  justed  by  a  regulating 
screw  I  to  withstand  the  desired  degree  of  at- 
traction before  moving  and  to  retain  the  snap 
switch  J  in  position. 

An  indicator  K  is  attached  to  the   cam-shaft, 
which  shows  the  relative  position  of  the  cam, 


FIG.  129. — DETAILS  OF  LIMIT  SWITCH. 

The  circuits  are  traced  as  follows:  Entering 
at  the  post  P  the  current  passes,  by  wire  1,  to 
one  of  the  spring  contact  pieces  E,  which,  in  its 
normal  or  "off"  condition,  rests  upon  the  insu- 
lating material  of  the  cam,  and  no  current  can 
pass.  As  the  cam  is  slowly  rotated  the  contact 
brushes  bear  upon  the  conducting-strips,  one  of 
which  is  electrically  connected  to  the  frame, 
and  thus  by  the  wire  2  through  the  resistance 
coil  to  wire  3  and  out  by  post  N.  When  both 
contact  pieces  bear  upon  the  cross-strip  M,  the 
current  passes  through  the  same  and  the  con- 
tact piece,  by  wire  4,  through  the  cut-out  and  to 
post  N,  short-circuiting  the  resistance. 

The  operation  of  the  apparatus  will  now  be 
readily  understood.  Supposing  the  indicator  to 
point  to  the  word  "off,"  the  spring  contacts 


FIG.  130. — DF.TAILS  OF  LIMIT  SWITCH. 

will  rest  upon  the  smallest  part  of  the  cam,  and 
as  the  strips  on  the  periphery  do  not  extend  to 
this  part,  the  contacts  will  rest  upon  the  insu- 
lating material  of  the  same  and  no  current  will 
pass.  If,  now,  the  handle  is  turned,  the  cam 
will  be  slowly  rotated,  bringing  the  conducting 
strips  under  the  spring  contacts,  and  as  these 


132 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATION^. 


strips  are  connected  to  the  resistance  coil,  the 
current  will  first  flow  through  the  coil,  and  the 
armature  of  the  motor  will  not  be  endangered; 
and  as  it  requires  a  number  of  turns  of  the 
worm  to  complete  the  rotation  of  the  varying- 
cam,  some  little  time  will  elapse  after  the  first 


FIG.  131. — SMALL  VAN  DEPOELE  MOTOR. 

contact  of  the  strips  with  the  spring  contacts 
before  they  will  reach  the  transverse  conduct- 
ing-strip,  when  the  resistance  will  be  cut  out 
and  the  direct  circuit  be  completed  through 
the  strip  and  spring  contacts,  permitting  the 
motor  to  have  the  full  force  of  the  current,  and 
the  indicator  will  point  at  "on."  It  will  be 
seen  that,  during  this  operation,  the  armature 
of  the  motor  will  have  attained  considerable 
velocity,  thus  developing  a  suitable  working- 
resistance  to  prevent  injury  to  the  brushes  or 
other  parts. 

As  stated  before,  there  is  a  cut-out  added, 
which  prevents  the  use  of  more  power  than  is 
contracted  for.  The  coil  of  the  cut-out  is  placed 
in  the  main  circuit,  and  the  armature  may  be 
adjusted  so  as  to  allow  a  current  of  a  certain 
specified  strength  to  pass  without  operating  it; 
but  any  abnormal  increase  due  to  overloading 
the  motor  or  otherwise  would  cause  it  to  be  at- 
tracted toward  the  magnet  core,  thereby  releas- 
ing the  snap-switch  and  breaking  the  circuit. 
The  adjusting  screws  permit  of  regulation  for 
a  wide  range  of  current,  and  can  be  adjusted 
for  any  desired  consumption  of  power.  The 
cut-out  box  is  kept  locked  and  under  the  con- 
trol of  the  parties  at  the  central  station,  and 
the  consumer  is  limited,  therefore,  to  the  use 
of  the  amount  of  power  contracted  for.  In  the 


event  of  an  attempt  to  take  more  power  than 
contracted  for,  the  speed  of  the  armature  is  re- 
duced, the  internal  resistance  of  the  machine 
being  thereby  decreased,  the  flow  of  the  current 
will  quickly  reach  the  point  at  which  the  ad- 
justable cut-out  has  been  set,  when  the  circuit 
is  severed  and  the  consumer  is  obliged  to  notify 
the  company  before  the  machinery  can  be  placed 
in  working  order  again.  The  use  of  the  grad- 
ually increasing  cam  is  also  valuable  in  pre- 
venting the  operation  of  the  cut-out  when  the 
machine  is  started,  as  otherwise  an  abnormal 
flow  of  current  is  likely  to  occur  which  would 
operate  the  cut-out.  It  also  furnishes  a  safe 
and  effective  stop-switch,  for  as  soon  as  the  in- 
creasing cam  in  its  rotation  causes  its  highest 
part  to  pass  the  spring  contacts,  they  will  in- 
stantly fall  upon  the  smallest  insulated  part  of 
the  cam,  thus  severing  the  circuit  without  the 
possibility  of  forming  an  arc  for  any  appre- 
ciable time.  If  at  any  time  there  should  be  a 
sudden  abnormal  increase  in  the  current  in  the 
line  from  any  cause,  the  cut-out  operates  to 
prevent  injury  to  the  machine. 

We  illustrate  next  two  industrial  types  that 
have  been  made  by  the  Van  Depoele  Company. 


Fit 


DKIMIKLE  MOTOR. 


Fig.  131  shows  the  small  motor  for  light  work. 
The  principle  of  construction  will  be  easily  seen 
from  the  cut.  The  ring  armature  has  numer- 
ous sections,  insuring  steady  motion,  and  the 
pole  pieces  are  of  special  form.  The  design  of 
the  whole  is  simple  and  symmetric;  there  are 
no  parts  to  get  out  of  order,  and  with  a  few 


INDUSTRIAL  APPLICATION  OF   ELECTRIC  MOTORS  IN  AMERICA. 


133 


drops  of  oil  occasionally,  these  motors  will  run 
for  years  without  the  slightest  irregularity,  and 
without  perceptible  wear.  The  battery  fur- 
nished with  them  is  a  bichromate,  of  improved 
pattern,  which  can,  of  course,  be  connected 
with  or  disconnected  from  the  motor  at  will  by 
means  of  a  switch,  and  can  be  put  away  in  any 
convenient  place  in  a  box. 

Fig.  132  is  a  motor  for  running  large  horizon- 
tal fans,  which  can  be  coupled  directly  witfi  the 
vertical  shaft.  When  it  is  necessary  to  run 
several  fans  at  once,  instead  of  using  several 


The  base  carries  the  upper  core  and  pole  of 
the  field  magnet  attached  permanently  to  it. 
The  under  core  and  pole  is  hinged  at  the  rear 
of  the  motor  just  above  the  binding  post  there 
shown.  It  is  so  hinged  for  the  purpose  of 
changing  the  speed  of  the  motor  to  suit  require- 
ments by  moving  the  under  pole  to  or  from  the 
armature  by  means  of  a  connecting  rod  and 
treadle  not  shown. 

When  the  pole  is  moved  away  from  the  arma- 
ture its  attractive  influence  is  not  so  strong, 
and  therefore  the  power  and  speed  are  decreased. 


FIG.  133. — DIKHL  MOTOR. 


motors,  one  motor  of  sufficient  power  for  the 
lot  can  be  used,  with  the  intervention  of  belting 
in  the  ordinary  way. 

At  the  Singer  Manufacturing  Company's  ex- 
hibit in  the  International  Electrical  Exhibition 
at  Philadelphia  in  1884  were  seen  several  sew- 
ing machines  run  by  various  electric  motors 
invented  by  Mr.  Philip  Diehl,  the  inventor 
engaged  by  the  sewing  machine  company,  and 
one  whose  other  work  in  the  practical  appli- 
cation of  electricity  has  been  marked  by  great 
originality. 

One  form  of  motor  is  made  part  of  the  fly- 
wheel of  the  sewing  machine,  and  the  one  we 
illustrate  by  Fig.  133  shows  the  motor  at  about 
two-thirds  size. 

17 


If  the  pole  be  swung  downward  until  its  lowest 
limit  is  reached,  the  electric  circuit  is  broken 
entirely  at  the  point  where  the  button  on  the 
under  pole  and  the  spring  projecting  from  the 
upper  pole  meet.  The  post  with  the  two  jam 
nuts  on  it  is  for  the  purpose  of  fixing  the  posi- 
tion of  the  upper  pole. 

The  armature  core  axis  and  pulley  are  cast  as 
one  piece  of  iron,  and  the  armature  is  of  the 
Siemens  H  type.  One  pole  of  the  armature  core 
is  extended  and  bent  so  that  the  axis  at  the 
commutator  end  is  in  its  proper  place,  and  there 
is  a  space  between  this  extension  and  the  other 
pole.  At  the  other  end  of  the  other  pole  a  like 
extension  for  the  pulley  axis  is  provided.  Thus 
there  are  longitudinal  and  transverse  spaces 


134 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


lengthwise  around  the  core  to  receive  the  coil; 
and  yet  the  poles  are  not  connected  by  iron  ex- 
cept within  the  coil. 

The  commutator  is  of  the  kind  usually  at- 
tached to  bipolar  armatures— that  is  to  say,  it 
has  two  sections. 


which  is  also  carried  by  journal  bearings  in  the 
side  rods. 

The  method  of  regulation  of  the  motor  con- 
sists in  separating  the  pole  pieces  from  the  arma- 
ture. This  is  accomplished  by  means  of  two 
connecting  rods  fixed  to  the  lower  ends  of  the 
magnets  and  joined  together  by  a  pin  which 
lides  in  a  slot  on  the  upright.  A  rod  connected 
to  the  pin  serves  to  raise  and  lower  the  upper 
ends,  of  the  two  connecting  rods,  and  in  doing 
so  the  field  magnets  are  separated  or  brought 
together,  as  the  case  may  be. 


FIG.  134 — DIKIII.  MOTOR. 

One  of  the  most  novel  and  ingenious  of  recent 
motors  is  that  shown  in  Fig.  134.  This  motor  is 
also  the  invention  of  Mr.  Diehl.  The  present 
motor,  though  built  on  the  same  principle  as 
the  one  exhibited  by  the  inventor  at  Philadel- 
phia, 1884,  and  illustrated  above,  differs  con- 


FIG.   135. — KEF.GAN  MOTOK. 

siderably  from  it  in  construction  and  general 
appearance. 

By  referring  to  the  engraving,  it  will  be  seen 
that  the  field  magnets  are  placed  vertically  and 
liinged  at  the  top,  being  supported  by  two  side 
rods,  cast  solid  with  the  base.  The  lower  ends 
of  the  field  magnets  encircle  the  armature. 


Fio.   136. — PEN  n  [.ETON  MOTOR. 

When  used  in  connection  with  a  sewing  ma- 
chine, the  motor  is  secured  to  the  under  side  of 
the  table  in  an  inverted  position,  and  the  reg- 
ulating lever  connected  to  the  treadle.  In  this 
position  the  field  magnets  fall  apart  of  their 
own  weight  and  the  machine  does  not  work. 
It  is  only  when  the  treadle  is  pressed  and  the 
magnets  are  brought  together  that  motion  is 
obtained.  It  is  evident  that  by  varying  the  dis- 
tance between  the  armature  and  the  magnets 
any  desired  speed  can  be  obtained  for  fast  or 
slow  work.  The  motor  is  finished  in  a  very  or- 
namental style,  and  runs  very  smoothly.  The 
armature  shaft  is  provided  with  a  pulley,  and 


INDUSTRIAL  APPLICATION  OF   ELECTRIC   MOTORS   IN  AMERICA. 


135 


its  end  is  bored  so  that  the  power  can  be  trans- 
mitted by  belt  or  applied  directly,  as  when  driv- 
ing a  fan. 


FIG.  137. — ARMATTRK  OF  I'ENDLETON  MOTOK. 

Another  good  motor  recently  devised  for 
small  work  is  that  of  Dr.  V.  E.  Keegan,  of  Bos- 
ton. The  main  objects  sought  have  been  those 


five  volts  for  the  standard  size,  according  to  the 
power  required.  The  motor,  which  is  made  by 
Mr.  Wm.  J.  Keenan,  of  Boston,  is  neatly  built. 
The  commutator  is  platinized  to  prevent  corro- 
sion. 

At  a  meeting  of  the  electrical  section  of  the 
American  Institute,  held  in  New  York,  in  July 
of  the  present  year,  Mr.  John  M.  Pendleton  ex- 
hibited to  the  society  a  small  electric  motor  of 
his  own  design  which  embodies  several  novel 
features.  Mr.  Pendleton  remarked  that  the 
general  introduction  of  electricity  had  drawn 
considerable  attention  to  electric  motors,  from 
the  recognized  fact  that  power  is  not  only  more 


FIG.  138. — PENDI.ETON  MOTOR. 


of  simplicity  of  apparatus  and  economy  in  run- 
ning. As  the  illustration  shows — Fig.  135 — the 
motor  consists  of  two  horseshoe  electro-mag- 
nets, the  one  acting  as  field,  the  other  as  the 
armature.  The  pole  pieces  are  extended  in- 
wards until  they  come  within  a  quarter  of  an 
inch  of  each  other,  and  at  this  point,  where  the 
magnetism  is  the  strongest,  each  takes  the  form 
of  a  semicircle;  thus,  instead  of  an  alternate 
action  of  attraction  and  repulsion,  the  two  forces 
are  always  acting  together,  and  hence  the  effect 
of  the  induction  current,  according  to  the 
inventor,  is  largely  neutralized.  In  order  to 
make  the  motor  economical  of  battery  material, 
it  is  wound  for  high  resistance,  requiring  a  cur- 
rent of  only  two  amperes  at  from  ten  to  twenty  - 


readily  transmitted  by  electricity,  but  also  on 
account  of  the  facility  with  which  it  may  be 
subdivided  and  distributed  without  loss — a  point 
in  which  neither  steam  nor  gas  engines  can 
compete  with  it. 

The  motor,  which  is  shown  in  perspective  in 
Fig.  13G,  weighs  forty  ounces,  and  is  capable  of 
developing  power  sufficient  to  run  a  sewing  ma- 
chine or  other  light  running  apparatus,  such  as 
a  dental  drill,  mallet,  or  a  fan. 

The  armature  of  the  motor,  which  is  shown 
detached  in  Fig.  137,  is  of  the  three-pole  type, 
and  each  of  the  three  segments  of  the  commu- 
tator is  consecutively  cut  out  in  such  a  manner 
as  to  reverse  the  polarity  of  the  pole  of  the  ar- 
mature so  that  for  one-half  the  distance  of  the 


136 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


pole-piece  attraction  takes  place,   and  during 
the  other  half  repulsion. 

This  construction  obviates  any  dead  point, 
and  the  motor  starts  instantly  at  any  position  of 
the  commutator.  This  is  evidently  an  indis- 
pensable quality  in  a  motor  designed  to  operate 
intermittently,  stopping  and  starting  at  frequent 
intervals.  Such  work  also  frequently  requires 
a  change  in  speed,  so  as  to  run  fast  or  slow,  and 
this  has  also  been  provided  for,  by  making  the 
brush-holder  adjustable.  The  latter  is  con- 
trolled by  a  spring  which  normally  maintains 
it  at  the  position  of  maximum  speed.  By  ro- 


tating the  brush-holder,  however,  the  position 
of  contact,  and  hence  the  speed,  can  be  varied 
at  will  from  the  maximum  down.  This  shifting 
of  the  brushes  does  not  require  any  manipula- 
tion by  hand,  but  is  accomplished  by  a  cord  at- 
tached to  a  treadle,  thus  leaving  the  operators 
hands  free  to  guide  the  work. 

The  engraving,  Fig.  138,  shows  a  larger  size 
of  the  same  type.  The  latter  weighs  twenty 
pounds,  and  is  said  to  be  able  to  develop  as  high 
as  one-quarter  horse  power. 

(The  latest  American  motors  of  the  industrial 
class  will  be  found  in  Chapter  XII.) 


CHAPTER  X. 


BLECTRIC  MOTORS  IN  MARINE  AND  AERIAL  NAVIQATION. 


THE  use  of  electric  motors  in  marine  and 
aerial  navigation  has  been  chiefly  studied  with 
a  view  to  obtaining  the  necessary  current  from 
storage  batteries.  It  is  true  that  bichromate  of 
potash  has  been  employed,  but  storage  is  re- 
garded by  almost  all  who  have  investigated  the 
subject,  as  the  ultimate  means  to  be  adopted  in 
any  practical  work  on  a  large  scale. 

The  experiments  on  the  Neva,  fifty  years  ago, 
have  already  been  noticed.  There  is  nothing 
to  record  in  the  present  chapter  from  the  efforts 
of  Jacobi  until  we  come  to  those  of  the  ingen- 
ious and  versatile  Trouve  of  Paris,  who  put  a 
small  electric  boat  on  the  lake  at  the  exhibition 
in  1881.  This  boat,  which  had  previously  been 
shown  in  operation  on  the  Seine,  was  equipped 
with  a  double  motor,  or,  in  other  words,  with 
two  bobbins  put  close  together  fixed  on  the 
rudder-head.  The  current  was  furnished  by  a 
bichromate  of  potash  battery  placed  in  the 
middle  of  the  boat.  Motion  was  communicated 
by  means  of  an  endless  chain  to  a  small  screw 
fitted  in  the  rudder  itself.  A  speed  of  about 
three  and  one-half  miles  was  obtainable,  with 
a  load  of  four  or  five  passengers,  and  the  bat- 
tery was  only  active  when  wanted. 

The  launch  "  Electricity,"  operated  on  the 
Thames  in  1882,  is  said  to  have  been  the  third 
boat  propelled  by  an  electric  motor.  It  was 
twenty-five  feet  in  length  and  about  five  feet  in 
the  beam,  drawing  one  foot  nine  inches  forward 
and  two  feet  six  inches  aft,  and  was  fitted  with  a 
twenty-two  inch  propeller  screw.  On  the  trial 
trip  on  the  Thames  there  were  stowed  under 
the  flooring  and  seats  forty-five  electric  accu- 
mulators of  the  Sellon-Volckmar  type,  which 
had  been  charged  by  wires  leading  from  dyna- 
mos, and  were  calculated  to  supply  power  for 
six  hours  at  the  rate  of  four  horse  power. 
These  storage  cells  were  placed  in  electrical 
connection  with  two  Siemens  dynamos,  fur- 
nished with  special  reversing  gear  and  regula- 
tors, to  serve  as  motors  to  drive  the  screw- 


propeller,  the  arrangement  being  such  that 
either  or  both  of  the  motors  could  be  switched 
into  circuit  at  will.  The  party  on  board  con- 
sisted of  four  persons,  Mr.  Volckmar  being  one 
of  the  number.  The  launch  would  carry  twelve 
passengers.  The  ability  of  the  boat  to  go  for- 
ward, slacken,  or  go  astern,  at  the  pleasure  of 
the  commander,  was  satisfactorily  tested,  and 
a  speed  of  eight  knots  an  hour  was  made 
against  the  tide.  The  return  trip  from  London 
Bridge  to  Millwall,  coming  down  with  the  ebb, 
was  made  in  twenty-four  minutes,  the  mean 
speed  of  the  vessel  being  nine  miles  per  hour. 
The  actual  expenditure  of  electric  energy  was 
calculated  to  be  at  the  rate  of  three  and  one- 
eleventh  horse  power. 

During  1883,  a  launch  built  by  Messrs.  Yar- 
row, of  England,  and  shown  at  the  Vienna 
Electrical  Exhibition,  attracted  considerable  at- 
tention. The  boat  was  forty -six  feet  in  length, 
and  was  capable  of  accommodating  some  forty- 
nine  or  fifty  passengers — an  extraordinary  num- 
ber, in  comparison  with  the  carrying  powers  of 
any  steam  launch  of  corresponding  dimensions. 
The  whole  of  the  boat,  with  the  trivial  excep- 
tion of  a  small  space  at  the  stern — hardly  more 
than  is  sufficient  for  the  "  man  at  the  wheel  "- 
was  available  for  use  instead  of  having,  as  is 
the  case  of  the  best  constructed  steam  launches, 
a  large  portion  of  the  centre  of  it  occupied  by 
the  machinery.  Comfortable  seats  extended 
through  the  entire  length  of  the  launch  on  each 
side,  and  there  was  nothing  to  interrupt  a  prom- 
enade from  end  to  end  of  it. 

The  motive  power  lay  perdu  in  seventy  boxes, 
each  of  one  horse  power,  stowed  away  under 
the  floor  of  the  launch,  and  at  the  end  there 
was  a  Siemens  D  2  type  of  motor,  the  spindle 
of  which  was  continued  so  as  to  form  the  shaft 
of  the  screw.  There  was  no  gearing  whatever 
between  the  dynamo  and  the  screw,  to  which 
600  to  800  revolutions  per  minute  could  be  im- 
parted without  the  slightest  noise,  and  a  speed 


138 


THE   ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


of  from  eight  to  nine  miles  an  hour  kept  up 
with  far  less  than  the  usual  amount  of  wash. 
There  was  no  noise  nor  heat,  nor  smell  of  ma- 
chinery, nor-  smoke,  and,  as  we  have  said,  the 
whole  of  the  boat  was  practically  available  for 
use,  without  any  obstruction  of  boilers  and  en- 
gines. The  advantage  of  such  a  motive  power 
is  thus  in  many  ways  quite  obvious,  and  the 
cost  of  the  launch  complete  in  every  respect 
was,  it  is  said,  only  about  63,000. 

Since  1883  various  other  trials  have  been 
made,  and  experiments  tried.  One  of  the  most 
successful  workers  along  this  line  has  been  Mr. 
Reckenzaun,  who  at  the  present  time  has  a 
launch  running  successfully  on  the  Thames 
fitted  with  his  motor  and  secondary  batteries. 

In  June,  1885,  Mr.  Reckenzaun  took  the  Duke 
of  Bedford  for  a  cruise  in  the  electric  launch 
"Australia,"  on  the  Thames.  The  Duke  was 
so  pleased  with  the  performance  of  the  "Aus- 
tralia "  that  he  decided  to  order  a  boat  of  simi- 
lar design,  but  of  more  elegant  appearance, 
and  the  Electrical  Power  Storage  Company  was 
intrusted  with  the  construction  of  the  pro- 
pelling apparatus  of  this  new  vessel,  which  is 
some  three  feet  longer  than  the  "Australia"; 
the  internal  arrangements,  however,  are  very 
similar.  Twenty-nine  E.  P.  S.  accumulators 
are  placed  in  a  box  in  the  centre  of  the  boat, 
this  box  serving  as  a  seat  for  passengers; 
the  cells  actuate  a  Reckenzaun  motor,  and  the 
speed  obtained  is  of  the  average  rate  of  six 
knots  per  hour  for  four  and  a  half  hours.  The 
accumulators  of  this  boat  serve  also  for  light- 
ing the  yacht  when  the  electric  launch  is 
suspended  from  the  davits,  and  the  cells  are 
charged  from  the  dynamo  which  usually  lights 
the  "Northumbria."  The  official  trial  took 
place  at  Westminster,  in  the  presence  of  numer- 
ous spectators.  Mr.  Reckenzaun  has  had  sev- 
eral designs  of  electric  boats  in  progress,  for 
some  time  past,  embodying  further  substantial 
improvements.  One  of  these  is  being  executed 
to  the  order  of  the  Italian  government,  and  a 
second  for  an  Indian  prince;  the  former  is  for 
war  purposes  and  the  latter  for  pleasure.  The 
prince's  launch  is  to  be  fitted  most  luxuriously, 
and  electrically  lighted,  even  the  fans  being 
actuated  by  electricity. 

During  September  of  the  present  year,  the 
launch  "Volta,"  fitted  with  two  Reckenzaun 
motors  and  a  set  of  accumulators,  made  the  trip 
from  Dover  to  Calais  and  back,  with  ease  and 


safety,  the  batteries  being  charged  but  once  for 
the  whole  journey.  The  "Volta"  is  37  feet 
long,  has  7  feet  of  beam  and  is  :i^  feet  deep. 
She  is  built  of  galvanized  steel  plates.  Her 
propelling  power  consists  of  sixty -one  accumu- 
lators, each  eight  inches  square,  placed  as  bal- 
last under  the  floor  with  the  motors.  The  ac- 
cumulators were  charged  over  night  from  a* 
dynamo  worked  by  a  small  steam  engine  in  a 
carpenter's  shop  facing  Dover  harbor,  the  con- 
nection to  the  boat  being  by  short  sections  of  a 
cable.  Seven  passengers  were  carried  and  a 
speed  of  over  six  miles  an  hour  was  main- 
tained, while  over  twelve  miles  was  reached. 

As  in  marine  navigation,  so  with  aerial — the 
use  of  electric  motors  has  been  of  an  experi- 
mental character,  and  yet  its  results  are  most 
significant  and  encouraging.  Up  to  1881,  one 
of  the  greatest  desideratums  in  ballooning  was 
a  light  motor  that  would  not  require  fire  and 
would  not  be  subject  to  loss  of  weight  in  oper- 
ating. Clearly,  the  electric  motor  was  the 
thing  wanted,  and  M.  Gaston  Tissandier  ap- 
plied himself  to  the  problem  of  adapting  the 
means  to  the  end.  In  a  note  to  the  French 
Academy  of  Sciences,  read  August  1,  1881,  he 
said:  "The  recent  improvements  made  in 
dynamo-electric  machines  have  given  me  the 
idea  of  employing  them  for  the  directing  of  bal- 
loons, combined  with  secondary  '  batteries, 
which  although  of  relatively  light  weight,  store 
up  a  large  amount  of  energy.  Such  a  motor, 
connected  by  a  propelling  screw,  offers  ad- 
vantages over  all  others,  from  an  aerostatic 
standpoint.  It  operates  without  any  fire,  and 
thus  prevents  all  danger  from  that  element 
under  a  mass  of  hydrogen.  It  has  a  constant 
weight,  and  does  not  give  out  products  of  com- 
bustion which  continuously  unballast  the  bal- 
loon and  tend  to  make  it  rise  in  the  air.  It  is 
easily  set  running  by  the  simple  contact  of  a 
commutator."  M.  Tissandier  carried  out  these 
ideas  in  a  model  with  which  he  experimented 
publicly  and  successfully  at  Paris,  during  the 
electrical  exhibition  of  1881.  He  then  went  to 
work  with  a  balloon  equipped  with  a  light 
Siemens  machine  and  a  bichromate  of  potash 
battery,  and  resolved  to  try  the  principle  of 
screw  propulsion.  Finally,  in  October,  1883,  he 
made  a  notable  experiment  near  Paris  with  a 
balloon  having  a  total  weight  of  1,240  kilo- 
grammes. Allowing  10  kilogrammes,  the  lifting 
force  was  1,250  kilogrammes.  The  bichromate 


ELECTRIC   MOTORS  IN   MARINE  AND  AERIAL  NAVIGATION. 


139 


FIG.  139.— VIEW  OF  THE  TISSANDIEK  BALLOOX. 


140 


THE   ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


of  potassium  batteries  were  composed  of  four 
troughs  with  six  compartments,  making  twenty- 
four  elements  in  circuit.  By  means  of  a  mer- 
cury commutator,  6,  12, 18,  or  24  elements  could 
be  used,  thus  giving  four  different  speeds  of 
the  screw,  varying  from  00  to  180  revolutions 
per  minute.  The  results  of  this  experiment 
were  summarized  by  M.  Tissandier  as  follows: 


FIG.  140. — BATTKKIES  OF  TISSANDIER  BALLOON. 

"We  have  concluded  from  this  first  trial 
that: — 1,  electricity  furnishes  a  balloon  with 
the  most  convenient  power,  the  management  of 
which  in  the  car  is  remarkably  easy;  2,  in  our 
own  case,  when  our  screw,  2.8  metres  in  diame- 
ter, made  180  revolutions  per  minute,  we  were 
able  to  keep  head  to  wind,  moving  three  metres 
per  second,  and,  when  proceeding  with  the  cur- 
rent, to  deviate  from  the  line  of  the  wind  with 
great  ease;  3,  the  mode  of  the  suspension  of  a 
car  from  an  elongated  balloon  by  means  of 
bands  running  obliquely  and  supported  by 
flexible  side-shafts,  insures  perfect  stability  to 


the  whole."  Our  illustrations,  Figs.  139  and  140, 
give  an  excellent  idea  of  the  appearance  of  the 
balloon  and  of  its  motive  mechanism.  The 
length  of  the  balloon  was  28  metres,  and  its  di- 
ameter at  the  centre  9.2  metres.  The  Siemens 
motor,  which  weighed  only  54  kilogrammes, 
had  an  armature  very  long  in  proportion  to 
its  diameter,  and  which  made  1,800  revolu- 
tions while  the  screw  to  which  it  was 
geared  made  180. 

The  speed  obtained  in  1883  was  three 
metres  per  second.  During  a  trip  made 
by  the  Tissandier  brothers  in  1884  a  speed 
of  nearly  four  metres  was  obtained,  and 
it  was  also  found  that  the  balloon  could 
be  brought  back  to  its  starting  point  even 
in  calm  weather.  The  next  noteworthy 
experiments  in  this  direction  were  those 
of  Capt.  Renard  and  Capt.  Krebs,  who  on 
August  9,  1884,  made  a  highly  successful 
demonstration  with  their  directible  bal- 
loon, the  outcome  of  six  years'  quiet  work, 
and  of  a  grant  of  100,000  francs  from  the 
French  government.  The  shape  of  the 
balloon  was  not  unlike  that  of  a  cigar 
pointed  at  both  ends.  The  car  suspended 
by  network  contained  seats  for  two  aero- 
nauts, the  motive  power,  and  the  steering 
apparatus.  Capt.  Renard  invented  for 
this  trial  a  secondary  battery  of  unusual 
lightness,  and  Capt.  Krebs  devised  the 
screw  and  rudder,  and  the  motor  gearing. 
The  dimensions  and  weights  were  these: 


Length  of  the  inflated  ellipsoid,  .     .     50  in.  42  cent. 

Central  diameter, 8  in.  40  cent. 

Volume, 1,864  cub.  in. 

Length  of  car — Nacelle, 33  m. 

Weights : 

.     869  kilos. 
127  kilos. 


Balloon  and  ballonet,  .     . 

Silk  covering  and  net,  .     . 
Car  complete  with  rigging,  etc., .     .     152  kilos. 

Rudder, 46  kilos. 

Screw-propeller, 41  kilos. 

Motor, 98  kilos. 

Wheelwork, 47  kilos. 

Shaft 30  kilos.  500  grams. 

Battery  complete, 435  kilos.  500  grains. 

Average  velocity  per  second, 5  in.  50  cent. 

Diameter  of  the  propeller, 7m. 

Number  of  revolutions  per  minute,      .     .     .     .     30  to  40 
Number  of  elements  employed 32 

The  electric  motor  was  constructed  to  develop 
8.5  horse  power  upon  the  shaft,  and  it  trans- 


ELECTRIC  MOTORS  IN  MARINE  AND  AERIAL  NAVIGATION. 


141 


mitted  its  motion  thereto  by  means  of  a  pinion 
gearing  with  a  large  wheel.  The  battery  was 
divided  into  four  sections,  that  could  be  connected 
either  for  quantity  or  for  potential,  and  was  cal- 
culated to  deliver  12  horse  power— 8,952  watts — 
to  the  motor  for  four  consecutive  hours.  The 
trip  was  made  in  the  neighborhood  of  Paris. 
In  his  official  report  to  the  Academy  of 
Sciences,  M.  nerve"  Magnon  said:  "The  bal- 
loon rose  to  an  elevation  of  fifty  metres  above 
the  ground,  at  which  elevation  it  was  kept  per- 


the  balloon  descended  gradually,  obliqued  right 
and  left,  forward  and  backward,  at  the  pleasure 
of  its  pilots,  and  finally  landed  exactly  at  the 
point  indicated."  The  time  occupied  in  making 
the  entire  circuit  of  7,000  metres  (about  five 
and  one-half  miles)  was  only  twenty-three 
minutes.  The  maximum  velocity  obtained  was 
nineteen  kilometres  per  hour.  In  later  trips 
an  average  velocity  of  twenty-five  kilometres 
was  shown  as  the  result  of  the  various 
improvements  in  details.  Here,  then,  was  the 


Fit;.  141. — THE  KREBS-RKNARD  HAI.I.OON. 


manently  by  Capt.  Renard,  Capt.  Krebs  ma- 
noeuvring the  rudder.  As  soon  as  the  propeller 
was  given  a  rotary  movement  the  aerostat  took 
its  course  toward  the  Hermitage  of  Villebon, 
which,  previous  to  the  ascension,  had  been 
designated  as  its  objective.  The  wind  at  this 
moment  moved  with  a  velocity  of  five  metres 
per  second,  and  the  balloon  moved  against  it. 
So  soon  as  arrived  at  its  destination  the  officer 
who  held  the  tiller  waved  a  flag,  the  signal  of 
return,  upon  which  we  saw  the  aerostat  luff, 
describe  majestically  a  half  circle  of  a  radius 
of  about  3()()  metres,  and  sail  back  to  Meudon. 
Upon  reaching  the  lawn,  whence  it  had  started, 

18 


attainment  of  practical  ballooning.  As  Col. 
Fred  Burnaby,  an  enthusiastic  aeronaut,  had 
said  but  a  short  time  before  in  discussing  the 
availability  of  electricity,  "to  put  the  case  in 
a  nutshell,  aerial  navigation  is  a  mere  question 
of  lightness  and  force,"  and  the  two  French 
officers  had  undoubtedly  succeeded  in  putting 
weight  and  strength  in  their  right  proportions 
to  be  effective.  M.  Gaston  Tissandier,  whose 
ample  experience  qualified  him  to  speak 
authoritatively  on  the  subject  remarked,  not 
only  with  generosity  but  with  truth:  "These 
new  experiments  are  decisive.  Navigation  of 
the  air  by  means  of  long  balloons  provided  with 


142 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


screws,  is  demonstrated.  We  will  repeat  what 
we  have  already  said  many  times,  that  to  be 
practicable  and  useful,  aerial  ships  must  be 
very  long,  of  very  large  dimensions,  which 
shall  carry  very  large  machines  capable  of 
giving  a  speed  of  from  twelve  to  fifteen  metres 
a  second,  allowing  their  working  at  almost  any 


time.  When  the  wind  is  high,  or  there  is  a 
squall  or  tempest,  aerial  ships  must  remain  in 
port,  as  other  vessels  do.  It  becomes  now  only 
a  question  of  capital." 

A  view  of  the  Renard-Krebs  balloon  described 
in  the  above  passages  is  given  in  Fig.  141, 
which  shows  also  its  starting  place. 


CHAPTER    XI. 


TELPHERAGE. 


WHILE  in  the  electric  railway,  as  in  electric 
lighting,  the  tendency  of  inventors  has  been  to 
preserve  old  forms  and  methods,  for  the  pur- 
pose of  more  easily  adapting  their  devices  to 
public  use,  in  what  is  known  as  "telpherage" 
a  decidedly  new  departure  is  taken.  Mr.  Her- 
bert Spencer,  if  we  remember  aright,  once 
drew  attention  to  the  survival  of  conventional 
curved  lines  in  the  bodies  of  the  English  rail- 
way cars,  which  thus  present  the  aspect  of 
the  old  and  obsolete  stage  coaches;  and  we 
might  instance  the  more  recent  case  of  incan- 
descent lighting,  in  the  introduction  of  which 
to  general  notice  and  use,  Mr.  Edison  sought  as 
far  as  possible  to  adhere  to  methods  that  had 
become  familiar  in  the  employment  of  gas. 
His  mains,  branches,  meters,  brackets,  "elec- 
troliers," and  switches  are,  practically,  so  many 
like  parts  of  a  gas-lighting  system,  and  may  be 
safely  left  to  the  handling  of  the  most  inex- 
pert; only  the  generating  apparatus  requires 
technical  skill  and  knowledge  on  the  part  of 
those  who  deal  with  it.  Some  may  say  that 
telpherage  is  after  all  simply  an  old  idea,  plus 
electricity,  but  we  believe  that  to  the  vast  ma- 
jority of  people,  the  transmission  of  freight 
or  passengers,  along  a  wire  road,  is  a  surprising 
innovation,  an  application  for  which  their  in- 
formation or  experience  can  find  no  parallel. 

The  word  "telpherage"  was  coined  by  the 
late  Professor  Fleeming  Jenkin,  who  conceived 
the  invention  now  being  developed  by  Professors 
Ayrton  and  Perry.  In  a  lecture  before  the 
University  of  Edinburgh,  Professor  Jenkin 
said:  "The  transmission  of  vehicles  by  elec- 
tricity to  a  distance,  independently  of  any  con- 
trol exercised  from  the  vehicle,  I  will  call 
'telpherage.'  The  word  should,  by  the  ordi- 
nary rules  of  derivation  be  'telpherage,'  but 
as  this  word  sounds  badly  to  my  ear,  I  ven- 
tured to  adopt  such  a  modified  form  as  con- 
stant usage  in  England  for  a  few  centuries 
might  have  produced;  and  I  was  the  more 


ready  to  trust  to  my  ear  in  the  matter,  because 
the  word  'telpher'  relieves  us  from  the  con- 
fusion which  might  arise  between  'telephore' 
and  'telephone'  when  written." 

Generically  considered,  a  telpher  line  sys- 
tem consists  of  a  rod  or  rail  track  of  con- 
siderable length,  suspended  several  feet  from 
the  ground,  connected  with  a  source  of  elec- 
tricity placed  at  some  suitable  and  convenient 
place  at  or  near  the  course  of  the  track,  and 

V?  Train    &vf'f~ft'fr  I'araliei  Aystom. 


JnsnUitd 


FT* 


FIG.  142. — DIAGRAM  OF  TELPHEHAGE  TRACKS. 

traversed  by  an  electro-locomotive  which  de- 
rives its  motive  power  electrically  from  the 
said  track,  draws  a  number  of  small  holders 
of  freight  or  passengers,  and  is  controlled,  as 
to  its  motion,  from  a  place  or  places  other  than 
itself. 

A  telpher  line  can  be  built  on  either  the 
"series"  or  the  "cross-over  parallel"  system. 
Figs.  142  and  143  show  the  "series"  system 
as  put  into  experimental  operation  at  Weston, 
Hertfordshire,  England,  about  two  and  a  half 
years  ago.  M  and  N  are  two  trains  of  cars 
running  on  the  line  upon  which  the  wheels 
bear.  The  line  has  make-and-break  mechan- 
ism at  </!  gz  gs,  points  about  120  feet  apart. 


144 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


These  make-and-breaks  are  normally  closed,  so 
that  a  current  of  electricity  may  flow  from  end 
to  end.  But  when  an  electric  train  is  started 
over  the  line,  say  from  left  to  right,  as  the  for- 
ward wheel  of  the  motor  strikes  the  make-and- 
break  glt  it  opens  the  circuit  by  moving  the 
latter;  and  then  the  current  takes  the  course 
through  to  the  rear  wheel  of  the  train,  the 
motor  thus  receiving  the  current  that  energizes 
it.  The  train  is  made  a  little  longer  than  the 


train  receives  no  current.  It  is  clear  that  any 
desired  number  of  trains  may  be  run  upon  the 
line  at  one  time,  it  being  necessary  only  to  have 
the  electromotive  force  adapted  to  the  number 
of  trains  operated.  In  the  larger  illustration 
of  the  series  system,  the  rough  posts  carry 
cross-arms  securely  bolted  to  them.  On  the 
overhanging  ends  of  these  arms,  are  the  junc- 
tion blocks  for  the  ends  of  the  sections.  These 
junction  blocks  are  placed  only  on  alternate 


FIG.  143. — VIEW  OF  "SERIES"  TELPHER  ROAD,  WESTON,  ENGLAND. 


120  feet  between  breaks,  so  that  when  the  for- 
ward wheel  strikes  break  gr2,  though  it  opens 
the  circuit  there,  the  current  still  flows  through 
the  train,  spanning  the  section  of  the  line 
from  </j  to  <72.  But  when  the  rear  wheel  of  the 
train  strikes  the  break  glt  it  closes  it,  so  that 
current  may  still  flow  through  the  line  and 
train.  As  the  train  moves  onward,  it  succes- 
sively opens  the  line  circuit  by  the  "break" 
under  its  foremost  wheel,  and  closes  the  line 
circuit  by  the  "make"  under  its  rearmost 
wheel,  so  that  the  current  for  the  motor  is  de- 
rived from  the  sections  of  the  track  under  the 
forward  and  rear  wheels  of  the  train,  at 
which  time  the  track  immediately  under  the 


posts,  because  the  posts  are  GO  feet  apart,  and 
the  sections  of  the  line  are  120  feet  in  length. 
The  intermediate  posts  carry  only  suitable  sup- 
ports for  the  line.  Fig.  142  represents  one  of 
the  junction  blocks.  Cast-steel  supports  A  and 
B  are  bolted  down  on  a  wooden  block,  which  is 
in  turn  bolted  to  the  ends  of  the  cross-arms;  or 
this  block  may  be  the  end  of  the  cross-arm 
itself.  The  upper  surfaces  of  A  and  B  are 
channelled  to  receive  the  conductors  W1  and 
W\  These  conductors  pass  one  on  each  side 
of  the  cast-steel  piece  C,  and  go  through  holes 
in  the  wooden  block,  being  secured  in  the  latter 
by  nuts,  as  shown.  The  piece  C  is  bolted  on 
the  wooden  block  in  a  position  intermediate 


TELPHERAGE. 


145 


between  A  and  B,  but  is  insulated  from  them. 
This  piece  serves  as  a  continuation  between  the 
rods  Wl  and  W2  so  that  the  wheels  of  the  loco- 
motive and  skips  can  ride  from  W1  to  W*  with 
regularity  and  smoothness.  The  circuit  is  com- 
pleted either  by  ground,  a  conductor  for  the 
purpose,  or,  preferably  by  a  return  line  over 
which  the  locomotive  may  run.  The  wire  in 
this  line  is  five-eighths  of  an  inch  in  diameter. 
The  load  is  carried  in  seven  skips,  the  first  be- 
ing seen  in  Fig.  14:!.  About  half  a  ton  can  be 
put  into  each  skip  and  a  speed  obtained  of 
six  miles  an  hour. 


is  supported  by  what  is  practically  one  long, 
continuous  steel  rod;  but,  in  reality,  at  the  tops 
of  the  posts  the  rods  are  electrically  subdivided 
into  sections  and  joined  across  by  insulated 
wires,  one  of  which  can  be  seen  on  the  post  in 
the  foreground  of  Fig.  144,  which  gives  a  good 
idea  of  the  line  in  actual  operation.  To  pre- 
vent the  metallic  wheels  of  the  skips  from 
short-circuiting  the  two  sections  as  they  cross 
the  tops  of  the  posts,  there  are  insulated  gap- 
pieces,  also  to  be  seen  in  Fig.  144,  at  the  tops  of 
the  posts  where  the  steel  rod  is  electrically  di- 
vided. It  is  found  that  for  moderate  inclines, 


FIG.  144.— VIEW  OF  "  CROSS-OVER  PARALLEL,"  TELPHER  ROAD,  GLYNDE,  ENGLAND. 


The  principle  of  the  cross-over  parallel  sys- 
tem of  telpherage  is  best  shown  forth  in  a 
commercial  line  — Fig.  144 — recently  put  in 
operation  at  Glynde,  England,  for  the  New 
Haven  Cement  Company,  to  carry  clay  from  a 
pit  to  the  Glynde  railway  siding,  whence  it  is 
delivered  into  trucks  and  taken  by  rail  to  the 
cement  works.  Fig.  145  illustrates  the  con- 
struction of  the  track  for  two  trains.  D  is  the 
dynamo  furnishing  current  to  the  circuit  AI 
and  BI,  respectively,  positive  and  negative. 
The  wheels,  L  and  P  of  one  train  and  I/t  and 
P!  of  the  other  are  insulated  from  their  trucks 
and  connected  in  the  case  of  each  pair  by  a 
wire  on  the  motor.  Consequently  as  the  trains 
move,  a  current  is  always  passing  from  a  posi- 
tive section  of  the  line  to  a  negative  section 
through  each  motor.  Mechanically,  each  train 


direct  driving  with  pitch  chains,  of  two  wheels 
with  india  rubber  treads,  gives  a  gravitation 
grip  sufficiently  strong  for  haulage  purposes. 
In  the  earlier  lines,  Ayrton  and  Perry  motors 
were  used;  in  this,  the  Reckenzaun  has  been 
tried. 

The  automatic  governing  of  the  speed  of  the 
train  is  effected  in  two  ways, — first,  there  is  a 
governor  attached  to  each  motor,  which  inter- 
rupts the  electric  circuit,  and  cuts  off  the 
power  when  the  speed  becomes  too  high;  sec- 
ondly, there  is  a  brake  which  is  brought  into 
action  should  the  speed  attain  a  still  higher 
value.  To  avoid  the  formation  of  a  permanent 
electric  arc  when  the  circuit  is  broken,  the  gov- 
ernor (Fig.  14G)  is  so  arranged  that  the  diverg- 
ing weights  are  in  unstable  equilibrium  be- 
tween two  stops:  they  fly  out  at  about  1,700 


146 


"THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


revolutions  per  minute  of  the  motor,  and  fly 
back  at  about  1,600.  When  the  circuit  is  closed, 
the  current  is  conveyed  across  the  metallic  con- 
tact at  C.  When  the  weights  W  W  fly  out, 
this  contact  is  first  broken,  but  no  spark  occurs, 


In  this  line  which  has  now  been  working  for 
nearly  a  year,  the  steel  rods  are  three-fourths 
of  an  inch  in  diameter  and  are  supported  on 
wooden  posts  about  eighteen  feet  high,  at  either 
end  of  the  cross-piece,  which  is  eight  feet  long. 


®-^ 


B, 


L, 


FIG.  145. — DIAGRAM  OF  GLYXDE  TRACK. 


because  a  connection  of  small  resistance  is  con- 
tinued at  B  between  the  piece  of  carbon  and  a 
piece  of  steel,  which,  being  pressed  out  by  a 
spring,  follows  the  carbon  for  a  short  distance 
as  the  arm  A  begins  to  fly  out.  This  contact  is 
next  broken,  producing  an  electric  arc;  which, 


The  skips  are  trough-shaped.  Each  holds 
about  two  hundred  weight,  and  is  suspended 
from  the  line  by  a  light  iron  frame,  at  the 
upper  end  of  which  is  a  pair  of  grooved  wheels 
running  on  the  line  of  rods.  Ten  of  these 
skips,  five  each  side  of  the  motor,  make  up  a 
train.  At  the  charging  end  of  the 
telpher  line,  the  skips  are  loaded 
each  with  about  two  hundred  weight 
of  clay,  the  train  thus  carrying  one 
ton.  A  laborer,  by  touching  a  key, 
starts  the  train,  which  travels  at  a 
speed  of  from  four  to  five  miles  an 
hour  along  the  overhead  line  to  the 
Glynde  station.  Arrived  there,  another 
laborer  upsets  each  skip  as  it  passes 
over  a  railway  truck,  into  which  the 
clay  is  thus  loaded.  This  upsetting, 
however,  will  eventually  be  performed 
automatically  by  means  of  a  lever  on 


FIG.  146. — TELPHER  GOVERNOR. 

however,  is  instantly  extinguished  by  the  lever 
A  flying  out  to  the  dotted  position.  The  brake 
is  shown  on  Fig.  147,  and  consists  simply  of  a 
pair  of  weights,  W  W,  which,  at  a  limiting 
speed  greater  than  1,700  revolutions  per  minute 
of  the  motor,  press  the  brake-blocks  B  B 
against  the  rim  C  C,  and  introduce  the  neces- 
sary amount  of  retarding  friction.  In  prac- 
tice, however,  with  the  gradients  such  as  exist 
at  Glynde,  and  which  do  not  exceed  one  in 
thirteen,  the  economic  method  of  cutting  off 
the  power  automatically  with  the  governor  is 
all  that  is  necessary  to  control  the  speed  of  the 
train,  the  brake  rarely  coming  into  action. 
With  steeper  gradients,  the  brake  would  be  of 
more  service. 


FIG.  147. — TEi.niKK  BKAKK. 


TELPHERAGE. 


147 


each  skip,  which  will  come  in  contact  with  a 
projecting  arm  as  it  passes  over  the  truck. 

The  laborer  at  the  discharging  end  of  the 
line  has  full  control  over  the  train,  and  can 
stop,  start,  and  reverse  it  at  will,  as  can  also 
the  man  at  the  other  or  loading  end.  There  are 
two  trains  at  Glynde,  but  only  one  is  at  present 


$6,000,  that  sum  including  outlay  for  an  equip- 
ment to  consist  of  stationary  steam  engine, 
generating  dynamo,  and  five  trains  with  elec- 
tro-locomotives, with  a  capacity  to  carry  over 
a  hundred  tons  daily.  The  total  cost  of  opera- 
tion is  put  at  six  cents  per  ton  of  material  car- 
ried. The  figures  of  the  Telpherage  Company 


FIG.  148. — CHAXDI.KK  SYSTKM  OF  STSI-KN-SION  TRANSPORTATION — ELEVATION  or 

LOCOMOTIVE  CAR. 


used,  that  being  found  sufficient  to  deliver  150 
tons  of  clay  per  week  at  the  station.  The 
trains  need  no  attention  when  running,  as  they 
are  governed  to  run  at  the  same  speed  both  on 
rising  and  falling  gradients.  An  automatic 
block  system  is  provided,  so  that  as  many  as 
twenty  trains  can  be  run  on  the  line  without 
the  possibility  of  collision. 

As  a  few  figures  in  regard  to  expense  will  be 
interesting,  it  may  be  stated,  that  such  a  tel- 
pher line  as  that  at  Glynde  can  be  put  up  for 


of  London  show  a  cost  of  about 
$50,000  for  a  line  ten  miles  long, 
to  carry  30,000  tons  of  freight 
yearly.  It  need  hardly  be  pointed  out  that  such 
lines  can  be  made  important  feeders  for  main 
lines  of  railway.  To  quote  once  more  from  the 
modest  but  brilliant  electrician,  the  late  Profes- 
sor Jenkin,  whose  ideas  have  been  carried  out  by 
his  associates,  Professors  Ayrton  and  Perry: 

"  Mineral  traffic  is  only  one  small  part  of  the 
work  which  these  lines  can  do.     Where  rail- 


148 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


ways  and  canals  do  not  exist,  telpher  lines  will 
provide  the  cheapest  mode  of  inland  convey- 
ance for  all  goods — such  as  corn,  coal,  root 
crops,  herrings,  salt,  bricks,  hides,  and  so  forth 
—which  can  be  conveniently  subdivided  into 
parcels  of  one,  two,  or  three  hundred  weight. 
In  new  colonies  the  lines  will  often  be  cheaper 
to  make  than  roads,  and  will  convey  goods  far 
more  cheaply.  Surely  I  am  not  too  sanguine  in 
expecting  that  great  changes  will  be  produced 
in  agriculture  by  these  new  facilities  for  trans- 


FIG.  149. — CIIAXDLKR  SYSTKM  OF  SUSPENSION  TRANS- 
PORTATION— END  VIEW  OF  CAR. 


FIG.  150. — SMALL  FREIGHT  CAR,  CHANDLER  SYSTEM. 

port,  coupled  with  the  delivery  of  power  at  will 
from  any  point  of  the  telpher  road.  It  must 
not  be  supposed  that  I  look  on  the  new  telpher 
lines  as  likely  to  compete  with  railways  or  in- 
jure their  traffic.  On  the  contrary,  my  feeling 
is  that  they  will  act  as  feeders  of  great  value 
to  the  railways,  extending  into  the  districts 
which  could  not  support  the  cost  even  of  the 
lightest  railway.  It  is  idle  to  endeavor  to  fore- 
tell the  future  of  any  new  idea;  but  this  much 
is  certain — a  novel  mode  of  transport,  offering 
some  exceptional  advantages,  will  be  publicly 
shown  on  a  practical  scale  to-day." 

A  system  of  this  nature,  for  transporting 
freight  and  passengers,  is  now  being  intro- 
duced by  the  Suspension  Transportation  Com- 
pany, of  Boston,  under  various  patents,  covering 


TELPHERAGE. 


149 


FIG.  151. — MOTOR  ox  CHANDLER  WIRK  ROAD.  FIG.  152. — PASSING  A  POLE  ON  CHANDLER  WIRE  ROAD 


FIG.  153. — DESIGN  FOR  MAIL  OK  COAST  SERVICE. 


19 


150 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


the  use  of  electricity,  steam,  or  other  motive 
power  for  aerial  transportation. 

The  general   modus    operandi  of    this  com- 
pany's system  for  an  electric  wire  road  is  well 


FIG.  154. — VAN  DKFOELE  TKLPHEK  SYSTEM. 

illustrated  in  the  accompanying  engravings. 
It  is  evident  that  such  a  system,  while  not  in- 
terfering with  the  cultivation  of  the  soil  or 
with  pasturage,  is  free  from  danger  to  man  and 
beast,  and  that  a  mere  right  of  way  is  sufficient 
without  the  cost  of  the  fee.  Again,  it  requires 
no  cuttings  or  fillings,  and  is  thus  adapted  to 
uneven,  rocky,  or  uncleared  land,  and  the  turn- 
ing of  sharp  curves  presents  no  obstacles.  In 
crossing  streams  no  bridges  need  be  used.  The 
opportunities  for  the  application  of  this  system 
are  vast,  and  the  variety  of  uses  to  which  it 
can  be  put  is  very  great,  both  in  cities  and  in 
the  country. 


An  experimental  line  of  this  character,  with 
a  capacity  for  transporting  several  tons  in 
weight  upon  the  cables,  is  now  in  successful 
operation  at  the  works  of  Mr.  Leo  Daft,  and 
the  details  of  the  system  will  prove  interesting. 

The  posts  that  carry  the  cables  are  placed 
thirty  feet  apart,  and  the  cables  are  supported 
upon  wrought-iron  brackets  bolted  to  them. 
The  cables  rest  upon  .rubber  strips  placed  in 
clamps  at  the  end  of  the  braces.  This  is 
clearly  shown  in  Figs.  148  and  149,  which  rep- 
resent the  locomotive  in  elevation  and  in  sec- 
tion as  it  appears  suspended  between  the 
cables.  The  latter  are  of  steel,  the  upper  being 
two  inches  in  diameter  and  the  lower  one  inch. 
These  are  placed  in  the  same  vertical  plane  and 
are  seven  feet  six  inches  apart.  The  current 
passes  from  the  upper  to  the  lower  cable,  the 
motors  being  in  parallel  or  multiple  arc  between 
them.  The  motor  within  the  car  is  geared  to  a 
large  wheel  mounted  upon  the  same  shaft  with 
the  forward  grooved  traction  wheel,  and  is 
pivoted  on  one  end,  so  that  all  slack  in  the  belt 
may  be  readily  taken  up.  The  braking  will  be 
accomplished  by  electrical  means,  but  hand 
brakes  are  also  provided  as  shown,  which  can 
be  applied  through  the  medium  of  the  long 
lever  entering  the  car,  the  other  end  of  the 
lever  being  attached  to  the  rod  connecting  the 
brake-shoes  on  the  two  wheels.  Two  safety 
catches  are  attached  to  each  car  and  are  placed 


FIG.  155. — VAN  DEPOELE  TELPHER  SYSTEM. 

alongside  the  upper  wheels.  They  prevent  the 
car  from  leaving  the  cable  in  case  of  a  running 
off  of  the  wheel. 

In  all  places  where  the  grade  is  much  above 
ground  it  is  proposed  to  stretch  a  safety  wire 
from  bracket  to  bracket,  thus  insuring  against 
accident. 


TELPHERAGE. 


151 


The  system  is  evidently  adapted  not  only  for 
the  transportation  of  goods  but  for  passenger 
traffic.  The  rate  of  speed  will  depend  on  the 
service  to  be  rendered;  as  high  as  twenty- five 
miles  an  hour,  and  even  more,  is  spoken  of. 

Fig.  150  shows  the  small  "freight  express" 
car  operated  successfully  for  several  weeks  at 
the  Novelties  Exhibition  in  Philadelphia  last 
year.  Figs.  151  and  152  illustrate  the  section  of 
track  now  in  use  experimentally  at  the  Daft 
Works,  Greenville,  N.  J.  The  illustrations  are 
made  from  photographs,  and  show  accurately 
the  slight  sag  in  the  wire  caused  by  the  passage 
of  the  car,  weighing  one  ton.  Fig.  152  shows 
the  manner  in  which  the  car  is  enabled  to  pass 
the  poles  on  the  line.  The  car  seen  carries  a 
small  Daft  motor  taking  its  current  from  the 
wire  cable. 

Fig.  153  is  an  illustrative  design  embodying  a 
plan  proposed  by  the  company  to  be  adopted  for 
mail  service  or  for  life-saving  service  along  the 
coast.  There  can  be  no  question  that  the  use 
of  such  a  device  would  immensely  expedite  the 


mail  delivery  between  New  York  and  Brooklyn, 
for  example,  or  could  be  applied  in  the  trans- 
portation of  mail  bags  from  the  general  post- 
office  to  the  Grand  Central  Depot.  The  saving 
in  time  alone  would  be  worth  a  great  many 
thousand  dollars  annually. 

The  "telpher"  system  devised  and  patented 
by  Mr.  C.  J.  Van  Depoele,  has  been  in  operation 
for  some  time  at  the  factory  of  his  company  in 
Chicago.  The  method  adopted  by  Mr.  Van 
Depoele  consists  in  suspending  the  car  upon 
two  cables  supported  by  pillars  and  cross-bars, 
as  shown  in  the  accompanying  illustrations, 
Figs.  154  and  155,  which  represent  respectively 
a  front  and  a  side  view  of  the  arrangements. 
The  hangers  D,  which  support  the  cables  F  F', 
are  insulated,  and  the  cables  themselves  form 
the  positive  and  negative  terminals  of  the 
motor.  The  band  wheels  K  K',  are  connected 
with  the  driving  wheels  of  the  electric  motor  C. 
Buffers  R  R  are  also  provided  at  the  ends  of  the 
rods  S  8,  the  inner  ends  of  which  are  provided 
with  buffer  springs. 


CHAPTER  XII. 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


SINCE  the  foregoing  chapters  were  written 
and  prepared  for  press — almost  entirely  as  they 
now  appear — phenomenal  activity  has  been  dis- 
played in  America  in  the  production  of  new 
motors  and  motor  systems.  It  has  therefore 
been  thought  well  to  bring  the  work  down  to 


FIG.  156. — THE'  STOCKWELL  MOTOR. 

date  by  including  all  the  latest  developments 
in  the  motor  field.  This  chapter  should  be  read 
in  connection  with,  and  as  supplementary  to, 
Chapters  VII.  and  IX. 

At  the  meeting  of  the  National  Electric  Light 
Association,  held  at  Detroit,  in  August,  1886, 
the  interesting  fact  was  brought  out  that  more 
than  5,000  electric  motors  of  all  sizes  were  in 
operation  in  this  country  at  the  present  time. 
Among  those  mentioned  as  being  largely  in 
use  was  the  Stock  well  motor,  which  has  for 


some  time  been  employed  in  the  running  of 
light  machinery,  especially  sewing  machines, 
and  it  is  said  that  not  less  than  a  thousand  of 
these  are  in  actual  service  to-day. 

The  motor,  which  we  illustrate  in  the  engrav- 
ing, Fig.  156,  is  enclosed  within  a  case,  one 
end  of  which  is  removed  so  as  to  ex- 
pose the  interior.  The  magnets  are 
of  the  converging,  consequent  pole 
type,  and  form  an  integral  part 
with  the  top  and  bottom  of  the  cas- 
ing. The  two  sides  are  cast  sepa- 
rate and  held  together  by  screws. 

The  armature,  or  more  correctly 
the  armatures,  for  there  are  two  of 
them,  are  shown  in  Fig.  157.  As 
will  be  seen,  they  are  of  the  Sie- 
mens shuttle-wound  type,  and  are 
placed  at  right  angles  to  each  other. 
The  commutator  has  four  segments 
and  the  terminals  of  the  wire  on  each 
armature  are  connected  to  opposite 
segments.  The  latter  are  not  made 
parallel  with  the  spindle,  but  are 
helical  in  shape,  so  that  there  is  no 
break  in  the  circuit  at  that  point, 
since  the  brush  passes  the  current 
to  one  armature  before  leaving  the 
other.  By  this  arrangement  only 
one  armature  is  in  action  at  one 
time.  Taking  the  one  to  the  right, 
for  example,  it  is  at  its  maximum 
effect  during  the  quarter  revolution,  when  the 
polar  faces  of  the  armature  are  approaching 
the  pole-pieces,  and  until  they  come  directly 
opposite  each  other.  During  the  next  quar- 
ter revolution  the  armature  is  cut  out  of  the 
circuit  entirely;  on  the  third  quarter  it  again 
comes  into  the  circuit  until  occupying  the 
same  relative  position  as  in  the  first  quarter; 
and,  finally,  in  the  fourth  quarter  it  is  again 
cut  out.  But  it  is  evident  that  during  each  of 
these  idle  periods  of  the  armature  to  the  right, 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


153 


that  to  the  left  comes  into  circuit  and  goes 
through  relatively  the  same  cycle  of  opera- 
tions. The  action  is  quite  analogous  to  that  in 
two  steam  engines  coupled  with  their  cranks  at 
right  angles  to  each  other.  While  one  is  pass- 
ing over  the  centre,  and  practically  doing  no 
effective  work,  the  other  is  in  the  position  of 


FIG.  157. — ARMATURE  OF  STOCKWKLL  MOTOR. 

maximum  power,  with  the  crank  at  right  angles 
to  the  line  of  stroke.  In  both  cases,  there  can 
be  no  dead  point,  and  the  motion  is  smooth  and 
continuous. 

Where  motors  are  applied  to  machinery  re- 
quired to  be  run  at  different  speeds,  some 
method  of  regulation  becomes  necessary,  and 
in  the  present  instance  this  has  been  worked 
out  in  a  very  simple  manner.  Where  the  mo- 


FHI.  158. — IV.itsi'ECTivE  OF  RESISTANCE  BOARD. 

tors,  as  usual,  are  connected  in  series  with  each 
other,  an  adjustable  resistance  is  provided 
which  is  contained  within  a  box,  such  as  that 
shown  in  perspective  in  Fig.  158,  and  in  section 
in  Fig.  150.  This  adjustable  resistance  is  placed 
in  a  shunt  to  the  motor  and  consists  of  a  series 
of  carbon  bars  of  gradually  decreasing  con- 
ductivity. As  the  switch  lever  is  passed  over 


the  successive  contacts,  increasing  resistances 
are  introduced  in  the  shunt,  which  consequently 
allows  more  current  to  pass  into  the  motor  and 
increases  its  speed  correspondingly.  The  spring 
attached  to  the  switch  lever  keeps  the  latter  in 
the  position  of  "no  current "  in  the  motor,  and 
by  attaching  a  cord  or  other  device  connected 
to  a  treadle,  the  operator  on  a  ma- 
chine has  both  hands  free  to  work 
with. 

The  carbon  resistance  bars  are  cop- 
per-plated at  their  ends  and  firmly 
clamped,  and    by   making   them  of 
gradually    decreasing    cross-section, 
a  relatively  greater  increased  resist- 
ance is  thrown  into  the  circuit  as  the 
switch  lever  passes  from  one  contact  to  another. 
A  wide  range  of  control  is  therefore  afforded 
with  a  comparatively  limited  movement  of  the 


FIG.  159. — DIAGRAM  OF  RESISTANCE  BARS. 

lever.  The  motor  is  provided  with  a  clamp,  so 
that  it  can  be  readily  attached  to  a  table  or 
work  bench. 

The  varying  loads  which  in  practice  are 
thrown  upon  an  electric  motor  driving  a  num- 
ber of  machines,  require  that  some  provision 
be  made  for  keeping  the  speed  constant  under 
each  change  of  condition.  Mr.  John  Beattie, 
Jr.,  of  Westport,  Mass.,  in  solving  the  problem 
employs  a  motor  whose  field  magnets  are  pro- 
vided with  several  independent  coils  upon  each 
leg,  as  shown  at  C,  Fig.  160.  Geared  to  the 
motor  there  is  a  governor,  D,  which  oscillates  a 
lever  K'  having  a  circular  rack  M  at  its  ex- 
tremity. The  latter  swings  a  lever  K,  which 
touches  both  the  terminals  L  of  the  field-mag- 
net coils,  and  those  of  a  corresponding  number 
of  resistance  coils  /,  at  L'.  The  lever  K,  as 
shown,  is  in  series  with  one  or  more  of  the  field- 
magnet  coils  which  are  in  parallel  circuit  and 


154 


THE  ELECTRIC   MOTOR  AND  ITS  APPLICATIONS. 


with  one  or  more  of  the  resistance  coils,  which 
are  also  in  parallel  circuit. 

It  will  now  be  readily  understood  that  any 
increase  of  speed  in  the  motor  operates  so  as  to 


FIG.  160. — BKATTIE  MOTOR. 

cause  the  substitution  of  one  or  more  of  the  re- 
sistance coils  for  a  like  number  of  field-magnet 
coils.  This  of  course  reduces  the  strength  of 
the  field  and  reduces  the  speed  of  the  motor  to 
its  normal  amount. 

The  armature  of  the  motor  employed  by  Mr. 
Beattie  is  provided  with  two  sets  of  grooves, 
Fig.  161,  P  P-,  parallel  with  the  armature  shaft, 
and  at  right  angles  to  these  run  a  series  of  deep 
annular  grooves  Q.  The  wires  are  wound  ac- 
cording to  the  method  of  Siemens. 

Recognizing  the  growing  importance  of  the 
electric  motor  in  the  field  of  applied  electricity, 
Mr.  C.  F.  Brush  has  for  some  time  past  de- 
voted his  attention  to  the  construction  of  a  mo- 
tor which  should  fulfil  the  conditions  required 
in  a  successful  prime  mover.  Steadiness  of 
power  and  constancy  of  speed  under  all  loads 
are  two  of  the  principal  objects  to  be  sought 


for,  and  in  the  new  motor  these  have  been  pro- 
vided in  a  very  ingenious  way. 

The  motor,  which  is  illustrated  in  the  en- 
graving, Fig.  102,  closely  resembles  the  Brush 
dynamo,  which  is  too  well  known  to  require  ex- 
tended notice ;  but  the  devices  added  to  the' 
machine  for  the  purpose  of  securing  the  advan- 
tages above  mentioned  are  decidedly  interest- 
ing, and  merit  a  detailed  description. 

It  will  be  seen  that,  mounted  on  the  shaft  be- 
tween the  commutator  and  the  journal  bearing, 
there  is  a  cylindrical  shell.  The  shell  contains 
the  governor  by  which  the  speed  of  the  motor 
is  maintained  constant.  The  mode  of  regula- 
tion adopted  by  Mr.  Brush  consists  in  causing 
the  governor  to  adjust  the  commutator  auto- 
matically with  relation  to  the  brushes.  To  this 
end  the  commutator  segments  are  mounted 
upon  a  sleeve  on  the  shaft,  so  that  they  can  be 
revolved  to  any  desired  extent  under  the  in- 
fluence of  the  governor. 

The  illustrations,  Figs.  103  and  104,  show  the 
governor  in  detail.  As  will  be  seen,  the  com- 
mutator brushes  C  C  remain  fixed,  and  loosely 
mounted  on  the  shaft  E  is  the  commutator 
sleeve  a,  which  turns  freely.  The  commutator 
sections  d  are  insulated  from  the  sleeve  o.  and 
are  connected  to  the  armature  bobbins  by  flexi- 
ble wires,  so  as  not  to  interfere  with  the  rotary 
adjustment  of  the  commutator.  To  the  inner 
periphery  of  the  cylindrical  shell  G,  which  is 
bolted  to  the  shaft,  the  governor  arms  H  H  are 


FIG.  161. — DETAILS  OF  BEATTIE  ARMATITRE. 

pivoted.  The  inner  free  ends  of  the  arms  are 
connected  to  the  opposite  arms  by  means  of 
spiral  springs  1 1.  In  addition,  the  arms  carry 
each  an  adjustable  weight  K.  The  links  L  L. 
attached  to  the  arms  H  H,  are  connected  to  a 
disc  upon  the  commutator  sleeve.  Hence,  it 
will  be  readily  understood  that  as  the  governor 
shell  rotates  with  the  pivoted  weights  K  K,  the 
latter,  by  centrifugal  force,  will  be  removed  to- 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


155 


ward  the  periphery  of  the  shell,  and,  through 
the  medium  of  the  connecting  links  L  L,  will 
impart  a  rotary  movement  to  the  commutator, 
varying  its  position  on  the  armature  shaft. 

The  action  of  the  governor  is  precisely  anal- 
ogous to  that  in  a  steam  engine.  When  in  a 
state  of  rest,  the  springs  draw  the  weights  to- 
ward each  other  and  maintain  the  commutator 
segments  at  the  maximum  point  of  effect  with 
relation  to  the  brushes.  When  current  is 
switched  on  to  the  motor,  the  governor  weights 
in  their  revolution  are  thrown  outward  and  ro- 


points  on  the  commutator  nearer  to  the  brushes, 
and  thereby  increase  the  speed  of  the  motor. 
On  the  other  hand,  should  the  speed  of  the  mo- 
tor be  increased  above  the  normal  rate,  owing 
to  an  increase  of  current-strength  or  to  a  de- 
crease of  load,  the  governor  balls  will  be  caused 
to  recede  from  each  other  and  rotate  the  com- 
mutator in  the  same  direction  as  that  of  the 
armature  shaft,  and  cause  the  maximum  points 
on  the  commutator  sections  to  be  moved  away 
from  the  brushes,  and  thereby  decrease  the 
speed  of  the  motor.  In  this  manner  provision 


FIG.  162. — BRUSH  MOTOR. 


tate  the  commutator,  carrying  the  maximum 
points  away  from  the  contact  points  of  the 
brushes  and  in  the  direction  of  rotation  of  the 
armature.  This  action  decreases  the  effect  of 
the  driving  current  until  a  point  is  reached 
where  the  effect  of  the  driving  current  is  bal- 
anced by  the  load  on  the  motor,  and  the  speed 
of  the  latter  remains  constant.  Now,  should 
the  speed  of  the  motor  be  retarded  by  a  de- 
crease of  current-strength  with  no  correspond- 
ing diminution  of  load,  or  by  an  increase  of 
load  with  no  increase  of  current-strength,  the 
governor  balls  will  be  retracted  and  drawn  to- 
ward each  other  by  the  spiral  springs,  and 
thereby  rotate  the  commutator  in  a  direction 
opposite  to  the  motion  of  the  armature  shaft, 
the  effect  of  which  is  to  move  the  maximum 


is  made  for  all  contingencies  affecting  the 
working  of  an  electric  motor.  The  parts  con- 
stituting the  governor  are  few  and  simple. 

Another  of  the  more  recent  systems  designed 
for  the  purpose  of  running  light  machinery  is 
exemplified  in  a  neat  combination  of  electric 
motor  and  battery,  designed  by,  and  named  af- 
ter, Messrs.  Curtis  and  Crocker  of  New  York. 

The  little  motor,  shown  in  Fig.  165,  is  series 
wound,  having  an  internal  resistance  of  .12 
ohm,  and  is  capable  of  carrying  a  current  of  16 
amperes  with  safety.  At  2,000  revolutions  it 
generates  a  counter  electromotive  force  of  six 
volts,  with  the  current  of  sixteen  amperes,  and 
is  said  to  exert  a  pull  of  five  pounds  on  the  cir- 
cumference of  the  pulley,  which  is  one  and  one- 
half  inch  in  diameter.  The  magnet  cores  and 


156 


THE   ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


pole-pieces  are  continuous,  and  are  wrought- 
iron  drop-forgings.  The  armature  of  the  motor 
is  of  a  novel  construction,  on  the  Gramme  prin- 
.ciple,  and  is  completely  enclosed,  so  as  to  ex- 
clude all  dust  and  keep  it  from  accidental  in- 
jury. 


FIG.  163. — DETAILS  OF  GOVERNOR,  BRUSH  MOTOR. 

In  connection  with  the  motor  there  is  made  a 
hattery  consisting  of  two  cells,  giving  an  elec- 
tromotive force  of  nearly  four  volts,  with  a  cur- 
rent of  from  eight  and  one-half  to  ten  amperes. 
The  chemicals  used  in  the  battery  are  made  up 
in  the  form  of  bricks,  which  are  dropped  into 


FIG.  164. — DETAILS  OF  GOVERNOR,  BRUSH  MOTOR. 

the  cells  filled  with  water  and  soon  bring  the 
battery  up  to  its  full  work.  This  makes  the 
handling  of  the  battery  very  convenient  for 
those  inexperienced. 

Another  feature  is  the  method  by  which  the 
speed  of  the  motor  can  be  regulated  for  fast  and 
slow  working.  This  is  accomplished  by  sus- 


pending the  zincs  of  the  battery  upon  a  lever 
so  that  they  can  be  immersed  to  any  extent  or 
raised  entirely  out  of  the  solution.  The  lever 
is  operated  by  hand,  and  falls  into  different 
notches.  The  strength  of  the  current,  depend- 
ing upon  the  extent  of  the  immersion  of  the 
zincs,  can  thus  be  regulated  to  any  extent,  and 
with  it  the  speed  of  the  motor. 

Since  the  days  of  Pacinotti  it  has  been  known 
that  dynamos  and  motors  are  reversible,  and  it 
is  now  known  that  it  is  almost  impossible  to 
put  any  assemblage  of  copper  and  iron  together 
which,  when  a  current  is  passed  through  it 
while  in  a  magnetic  field,  will  not  show  some 
evidence  of  motion.  For  some  years  past  dyn- 
amo construction  has  been  carried  to  a  very  high 


FIG.  165.— THE  "C.  &  C."  MOTOR. 

degree  of  efficiency,  and  machines  have  been 
built  which  would  convert  ninety-six  per  cent, 
of  the  mechanical  energy  delivered  to  them  into 
electricity.  Yet,  notwithstanding  this  fact  and 
the  assertion  of  Prof.  Henry  A.  Rowland, 
that  the  best  dynamo  must  be  the  best  motor, 
in  other  words,  that  the  best  apparatus  for  con- 
verting mechanical  power  into  electricity  must 
be  the  best  apparatus  for  converting  electricity 
into  mechanical  power,  a  statement  which  on 
its  face  carries  the  elements  of  truth,  electric 
motors  have  remained  for  a  long  time  a  subject 
concerning  which  most  literature  was  sadly  at 
fault,  both  the  theory  of  the  motor,  a  knowledge 
of  its  action,  and  its  practical  application  being 
remarkably  limited.  One  of  the  causes,  per- 
haps, of  the  difficulty  of  handling  this  subject, 
has  been  that  most  motor  experiments  have 
generally  been  conducted  with  crudely  made 
dynamo  machines,  and  without  any  definite  idea 


LATEST  AMERICAN   MOTORS  AND   MOTOR  SYSTEMS. 


157 


of  the  relations  that  exist  in  the  different  parts 
of  the  circuit.  The  terms  electromotive  force, 
potential,  current,  and  resistance,  in  their  rela- 
tion to  what  is  commonly  called  the  counter- 
electromotive  force  and  to  each  other,  have 
not  been  at  all  generally  understood,  nor  even 
the  law  of  the  electro-magnet  until  Deprez  and 
Hopkinson  began  their  researches  on  the  satura- 
tion of  iron.  Even  to-day  well-known  scientific 
men  differ  on  this  latter  law. 

Deprez  in  Paris,  Ayrton  and  Perry  in  London, 
and  Sprague,  among  others,  in  the  United 
States,  have  been  the  most  active  in  developing 
the  true  theories  of  motors.  Of  the  latter  little 
was  known  in  this  line  until  the  fall  of  1884, 
when  the  Electrical  Exhibition  was  held  in  Phil- 
adelphia. Mr.  Frank  J.  Sprague  had  for  some 
time  before  this  been  pushing  his  researches 
with  energy,  and  at  the  Philadelphia  Exhibition 
exhibited  a  number  of  machines  which  were 
the  first  of  the  kind  ever  shown.  These  ma- 
chines were  run  on  an  Edison  constant  potential 
circuit.  They  were  thrown  into  circuit  grad- 
ually with  a  very  strong  rotary  effort  or  torque, 
ran  at  constant  speed  with  brushes  at  fixed 
points,  and  without  any  evidence  of  sparking, 
under  all  loads  from  the  minimum  up  to  the 
maximum  allowed.  In  addition  to  those  ma- 
chines, Mr.  Sprague  showed  others,  one  of 
which,  starting  under  a  heavy  load,  could  be 
made  to  run  forward  or  backward,  fast  or 
slow,  at  will,  the  reversal  being  made  with  an 
ease  and  rapidity  and  freedom  from  sparking 
which  were  remarkable.  Another  machine 
could  be  made  to  run  in  either  direction,  and 
was  provided  with  adjustments  so  that  it  could 
be  made  to  run  at  different  determined  constant 
speeds  under  varying  loads.  Since  the  exhibi- 
tion of  these  machines,  all  of  which  were  ex- 
perimental and  many  of  which  are  now  in 
practical  use,  Mr.  Sprague's  progress  in  this 
work  has  been  remarkably  rapid.  Some  idea 
may  be  obtained  of  the  operation  of  some  of 
the  different  classes  of  machines  built  under 
the  Sprague  system  from  the  following  general 
explanations: 

A  motor  when  running  may  be  looked  upon 
as  a  dynamo  machine  propelled  by  a  current;  it 
has  a  field  magnet  like  any  other  dynamo;  it 
has  an  armature  situated  in  that  field  which, 
either  because  of  the  attraction  and  repulsion 
of  the  lines  of  force,  or  of  the  double  attraction 
and  repulsion  of  the  poles  which  are  set  up  in 
20 


the  armature  acting  on  the  poles  of  the  field 
magnet,  is  caused  to  rotate.  This  armature 
rotating  in  the  magnetic  field  has  an  electro- 
motive force  developed  in  it  which  is  precisely 
of  the  same  kind  as  would  be  developed  were 
the  motor  driven  by  a  belt  instead  of  by  a  cur- 
rent. The  strength  of  this  electromotive  force 
depends  upon  the  resulting  strength  of  field  and 
the  speed  of  the  armature.  This  electromotive 
force,  which  may  be  termed  a  motor  electro- 
motive force,  is  ordinarily  called  the  counter- 
electromotive  force,  because  it  is  opposed  to 
that  of  the  line  current  which  is  flowing  into 
the  motor.  The  difference  between  this  line 
electromotive  force  and  that  of  the  motor  is 
what  may  be  called  the  effective  electromotive 
force,  and  determines,  in  combination  with  the 
resistance  of  the  circuit,  the  strength  of  current 
which  will  flow  in  a  circuit  into  which  these 
elements  enter.  In  any  case  of  a  single  trans- 
mission from  a  dynamo  to  a  motor  the  combi- 
nation of  these  two  determines  the  differences 
of  potential  which  exist  in  the  different  parts 
of  the  circuit,  which  difference  of  potential  de- 
termines the  strength  of  current  which  will  flow 
in  any  derived  circuit.  This  counter-electromo- 
tive force  likewise  determines  the  efficiency  of 
a  motor  or  a  system  of  transmission  of  power. 

Motors  may  be  described  as  belonging  to  one 
of  three  different  systems.  First,  those  in 
which  the  field  magnet  is  excited  by  a  coil  in 
parallel  circuit  with  the  armature,  that  is,  in 
shunt  relation  thereto;  second,  those  in  which 
the  field  magnet  is  in  series  with  the  arma- 
ture circuit;  and  third,  those  in  which  there  is 
a  combination  of  these  two  circuits.  There 
are  in  addition  a  very  large  variety  of  each  of 
these  classes,  different  conditions  demanding 
different  performance.  Furthermore,  similar 
machines  may  be  placed  upon  three  different 
kinds  of  circuits,  their  performances  varying 
widely  in  each  case.  These  three  conditions 
are:  First,  the  case  of  special  transmission 
with  varying  potential  and  current;  second, 
constant  current  circuits  in  which  the  main 
current  is  kept  at  a  constant  quantity,  and 
third,  constant  potential  circuits.  The  special 
transmission  of  power,  unless  carried  out  under 
certain  well-defined  laws  based  either  upon  a 
constancy  of  current  or  constancy  of  potential 
at  some  definite  part  of  the  circuit,  is  unsatis- 
factory, but  if  made  according  to  a  law  no  dif- 
ficulties present  themselves. 


158 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


We  will  briefly  consider  the  action  of  these 
different  kinds  of  machines  on  two  classes  of 
circuits  only.  First,  on  the  constant  current 
circuit.  If  a  series  wound  machine  be  placed 
upon  such  a  circuit,  the  same  current  passing 
through  the  field  magnet,  it  will"  develop  a  con- 
stant torque,  which  torque  is  directly  propor- 
tional to  the  strength  of  the  field  magnet  and 
to  the  current  in  the  armature.  If  the  mass 
of  iron  is  sufficiently  great  this  torque  will  be 
directly  proportional  to  the  effective  ampere- 
turns  in  the  field  magnet,  and  the  work  done 
will  be  directly  proportional  to  the  speed.  If 
the  machine  be  at  rest  there  will  exist  a  dif- 
ference of  potential  at  the  terminals  of  the 
machine  equal  to  the  product  of  the  current 
and  the  resistance  of  the  machine.  When  run- 
ning, however,  an  electromotive  force  will  be 
developed  in  the  machine  and  the  potential  at 
the  terminals  of  the  machine  will  rise  by  the 
same  increment.  The  work  done  may  be  like- 
wise expressed  by  the  product  of  this  counter- 
electromotive  force  and  the  current,  or  e  C,  and 
is  independent  of  the  resistance  of  the  ma- 
chine. The  resistance,  however,  determines, 
in  combination  with  the  other  elements,  the 
total  efficiency  of  the  motor.  The  total  en- 
ergy expended  is  the  product  of  the  difference 
of  potential  existing  at  the  terminals  of  the  mo- 
tor and  the  current  flowing,  or  E  C.  The  effi- 

eC  e 
ciency  then  is ,  or  — ,  and  the  heat  wasted 

EC  E 
(E  —  e)  C. 

When  running  at  any  particular  speed  the 
work  will  be  increased  directly  as  the  field  mag- 
net strength  is  increased.  So  also  will  be  the 
economy.  The  heat  wasted  with  any  given  re- 
sistance in  a  machine  under  these  conditions  is 
a  constant.  The  direction  of  rotation  of  such 
a  machine  can  be  reversed  by  reversing  either 
the  armature  circuit  or  the  field  circuit;  if 
both  circuits  are  reversed,  then  the  machine 
will  run  in  the  same  direction.  For  many 
classes  of  work  this  kind  of  machine  is  ex- 
ceedingly useful,  because  it  admits  of  a  great 
range  of  hand  control.  If  such  a  machine, 
however,  be  put  on  ordinary  work,  and  this 
work  be  lightened  up,  the  machine  will  run 
faster  and  faster,  and  unless  the  field  is  weak- 
ened or  the  brushes  shifted  to  check  it.  the 
speed  will  practically  increase  without  limit. 
Every  change  of  speed  and  every  change  of 


load  is  accompanied  by  a  corresponding  change 
in  the  potential  which  exists  at  the  terminals 
of  the  machine.  Moreover,  on  a  constant  cur- 
rent, the  motors  being  in  series  with  each 
other  and  with  lamps,  this  continual  variation 
of  potential  is  apt  to  cause  trouble  011  the 
circuit,  especially  if  the  machines  are  not  au- 
tomatic, since,  as  already  stated,  with  any  fixed 
field  the  torque  is  constant,  the  work  done  is 
directly  proportional  to  the  speed.  The  machine 
has  the  highest  efficiency  when  running  at  the 
highest  speed. 

With  shunt  machines,  however,  the  action  on 
the  constant  current  circuit  is  much  different. 
Here  the  current  is  divided  in  two  circuits, 
such  division,  when  the  motor  is  at  rest,  being 
inversely  proportional  to  the  resistances  of  the 
two  parts  of  the  circuit.  With  such  a  motor, 
the  field  is  weakest  when  the  machine  is  at 
rest,  and  its  torque  or  rotary  effort  is  also  very 
weak.  If  the  load  be  not  too  great,  as  the 
speed  of  the  machine  increases  a  counter-elec- 
tromotive force  is  set  up,  the  potential  at  the 
terminals  of  the  armature  and  field  magnets 
rises,  the  current  in  the  armature  diminishes, 
and  that  in  the  field  magnet  increases.  Pro- 
vided there  is  sufficient  iron  in  the  field  mag- 
nets, the  torque  or  rotary  effort  will  vary  in  a 
decreasing  ratio  until  one-half  of  the  current  is 
flowing  through  the  field  magnet.  At  this  mo- 
ment the  machine  will  be  doing  its  maximum 
amount  of  work,  and  at  less  than  fifty  per  cent, 
total  efficiency.  If  the  work  be  lightened,  the 
machine  will  increase  its  speed  until,  when  the 
work  is  entirely  removed,  there  will  be  prac- 
tically no  current  through  the  armature;  all 
will  have  been  shunted  through  the  field  mag- 
nets, and  the  potential  at  the  terminals  of  the 
machine  will  be  at  the  maximum.  Such  a 
machine  will  do  the  same  total  work  at  two  dif- 
ferent speeds  and  efficiencies. 

If  a  machine  be  wound  with  a  double  set  of 
coils  it  will  behave  very  much  the  same  as  a 
shunt  machine  does,  its  field  magnet  being 
strengthened  in  a  more  or  less  rapid  ratio,  or 
being  kept  constant,  depending  upon  whether 
the  series  coil  is  cumulative  or  differential. 

Because  of  the  fact  that  constant  current  cir- 
cuits in  ordinary  use  deal  with  small  currents 
and  very  high  electromotive  forces,  and  do 
not  admit  of  such  perfect  regulation,  Mr. 
Sprague  has  preferred  ordinarily  to  work  the 
constant  potential  circuits,  although  some  of 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


159 


his  machines  are  running  on  the  constant  cur- 
rent circuits  for  other  than  automatic  work; 
that  is,  for  work  where  the  speed  is  under  con- 
trol and  where  the  work  done  for  a  given 
speed  is  constant. 

There  are  two  ways  by  means  of  which  a 
constant  current  motor  can  be  governed.  One 
consists  in  automatically  changing  the  counter- 
electromotive  force  by  changing  the  position 
of  the  brushes  on  the  commutator  to  positions 
more  or  less  removed  from  their  normal  one. 
To  this  objection  is  offered  because  the  proper 
position  for  the  brushes  of  any  machine  is  at 
the  points  of  least  sparking.  The  other  method 
consists  in  varying  the  counter-electromotive 
force  by  automatically  weakening  the  field  as 
the  load  is  diminished,  or  strengthening  it  as 
the  load  is  increased.  Several  methods  have 
been  proposed  for  doing  this,  generally  by  the 
action  of  a  centrifugal  governor.  To  this  also 
some  objections  are  raised.  Mr.  Sprague,  de- 
siring to  get  rid  of  all  such  rapidly  moving  ad- 
juncts to  motors,  is  now  engaged  on  a  totally 
new  system,  which  promises,  he  thinks,  entire 
freedom  from  these  defects. 

On  constant  potential  circuits  the  behavior  of 
these  different  classes  of  motors  is  entirely 
different. 

A  plain  series  wound  motor  when  there  is  suf- 
ficient iron  in  the  field  has  a  torque  propor- 
tional to  the  square  of  the  current  flowing 
through  it.  It  is  capable  of  exerting  a  great 
rotary  effort  and  doing  a  large  amount  of  work 
at  a  slow  speed.  The  range  of  speed  for  dif- 
ferent loads  is,  however,  great,  and  the  motor 
is  unfitted  for  ordinary  work  where  steadiness 
of  speed  is  an  object;  as  the  load  is  diminished, 
the  speed  increases  and,  if  thrown  off  entirely, 
the  motor  will  run  faster  and  faster,  the  field 
continually  growing  weaker  and  the  armature 
all  the  time  accelerating  its  speed  in  a  vain  at- 
tempt to  generate  an  electromotive  force  equal 
to  tiie  initial.  For  some  classes  of  work,  this 
kind  of  a  machine,  with  some  essential  modifi- 
cations, is  exceedingly  useful. 

( )n  the  other  hand,  the  shunt-wound  machine 
will  run  fairly  well  on  a  constant  potential 
circuit.  The  field,  being  excited  independently 
of  the  armature,  is  constant,  and  since  the  load 
varies  with  the  motor  electromotive  force, 
and  the  field  is  constant,  it  follows  that  the 
speed  must  vary  with  e.  The  torque  is  propor- 
tional to  the  current  in  the  armature,  and  the 


speed  will  be  slowest  with  the  greatest  load  and 
fastest  with  the  lightest,  that  is,  when  e  =  E. 
The  lower  the  resistance  of  the  armature,  the 
less  the  variation  in  speed. 

It  Is  with  the  third  class  of  motors,  when  used 
on  constant  potential  circuits,  that  the  difficul- 
ties which  are  involved  in  the  governing  of  a 
motor  entirely  disappear,  and,  without  the  use  of 
any  such  apparatus  as  centrifugal  governors  or 
movable  contacts,  it  becomes  possible  to  satisfy 
the  most  exacting  conditions,  both  as  regards 
efficiency,  steadiness  of  running,  power  to  start 
under  very  heavy  loads,  and  freedom  from 
sparking. 

When  Mr.  Sprague  first  proposed  his  constant 
speed  machines  for  constant  potential  circuits, 
he  enunciated  the  following  seemingly  para- 
doxical proposition: 

In  a  motor  with  the  armature  and  field  mag- 
net independently  supplied,  the  work  which 
the  motor  will  do  in  a  given  time,  its  economy 
and  efficiency,  are  all  independent  of  the 
strength  of  the  field  magnet,  provided  the 
translating  devices  intermediate  between  the 
motor  and  whatever  is  the  recipient  of  its 
energy  are  not  limited  as  to  the  rate  of  trans- 
mission of  the  motor  speed;  and  that  in  all 
cases  where  a  motor  is  working  on  a  constant 
potential  circuit  and  not  up  to  its  maximum  ca- 
pacity, in  order  to  increase  the  mechanical 
effect  either  of  speed  or  power,  or  both,  or  to 
compensate  for  any  falling  off  of  the  poten- 
tial on  a  line,  it  is  necessary  to  weaken  the 
field  magnets,  instead  of  strengthening  them, 
and  vice  versa. 

The  strength  of  the  field  determines  the  speed 
at  which  a  motor  must  run  to  get  a  required  ef- 
ficiency. With  a  given  initial  potential  at  the 
armature  terminals,  no  matter  how  the  load 
varies  from  the  maximum  allowed,  the  speed 
may  be  maintained  constant  by  changing  the 
strength  of  the  field;  such  strength  being  di- 
minished as  the  load  is  increased,  and,  vice 
versa,  increased  as  the  load  is  diminished. 

These  facts  may  be  demonstrated  as  follows: 

Let  us  consider  the  motor  current  as  derived 
from  mains  having  a  fixed  difference  of  poten- 
tial, and  the  motor  with  its  field  and  armature 
in  shunt  relation.  In  this  case  the  armature 
runs  with  a  velocity  dependent  upon  the  strength 
of  field,  the  initial  potential,  the  number  of 
turns,  resistance,  etc.,  of  the  armature,  and  the 
load,  and  a  counter-electromotive  force  is  set 


160 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


up  which  regulates  the  armature  current.  The 
higher  the  speed  the  greater  this  counter-electro- 
motive force.  Let  E  be  the  initial  and  e  the 
counter-electromotive  force,  and  r  the  resist- 
ance of  the  armature.  The  current  flowing  in 

E  —  e 
the  armature  is  then  —   — .     With  a  given  arma- 

r 

ture  and  given  field  e  varies  with  the  speed. 
The  power  at  any  given  speed  and  strength  of 
field  varies  with  the  current,  and  with  any 
given  current  varies  with  the  strength  of  field. 
The  total  work  done  is  the  product  of  the  speed 
by  the  work  per  turn,  and  since  the  speed  is  as 
e  and  the  work  per  turn  as  the  current 
E  —  e\ 

I ,  the  total  work  done  is  expressed  by 


^i 

( 


e(E-e) 


The  efficiency  is  the  ratio  — . 

E 


It  will 


be  seen  that  both  these  expressions — the  total 
work  done  and  the  efficiency — are  independent 
of  any  function  of  the  field,  but  depend  only 
on  the  initial  and  counter-electromotive  forces 
and  the  resistance  of  the  armature,  and  any 
given  value  of  e  can  be  attained  with  any 
strength  of  field  by  attaining  proper  speed. 

Considering  the  speed  of  machine  constant, 
its  field  alone  being  varied,  and  differentiating 


the  expression  for  work  done, 
de 


e  (E—e) 


we  have 


de  f  \ 

-(*-*<) 


as  the  rate  of  variation  of  work. 


It  follows  then  that  to  maintain  the  speed 
constant  with  a  current  of  constant  potential 
under  varying  loads,  when  the  load  increases 
so  that  the  speed  would  naturally  decline,  the 
field  is  weakened,  the  counter-electromotive 
force  diminished  and  armature  current  in- 
creased, the  tendency  to  reduced  speed  is  coun- 
teracted, and  there  is  an  increase  in  the  me- 
chanical effect — power.  For  a  decreased  load 
the  field  is  strengthened,  the  counter-electro- 
motive force  increases,  the  current  decreases, 
the  speed  remains  the  same,  and  the  power  is 
decreased. 

To  maintain  speed  or  power  constant  under 
varying  initial  potential,  if  the  potential  at  the 
motor  terminals  increases,  these  mechanical  ef- 
fects increase  or  tend  to  increase.  By  strength- 
ening the  field  an  increased  counter-electro- 
motive force  is  produced,  so  that  the  increased 


power  or  speed,  or  the  tendency  thereto,  is 
counteracted,  and  this  counteraction  may  evi- 
dently be  itself  considered  a  decrease  in  me- 
chanical effect,  whether  the  regulation  is 
performed  simultaneously  with  the  increase  of 
potential  or  before  or  after  such  increase.  If 
the  regulation  is  performed  simultaneously, 
with  a  gradual  change  of  potential,  there  may 
be  less  change  in  counter-electromotive  force 
or  armature  current;  but  there  is  still  the  coun- 
teracting of  the  tendency  to  increased  mechan- 
ical effect,  which  counteracting  is  itself  a 
decrease  of  mechanical  effect.  For  a  decreased 
or  decreasing  initial  potential,  the  field  is  weak- 
ened to  counteract  the  decrease  in  mechanical 
effect  which  would  otherwise  occur,  and  there- 
fore to  produce  an  increased  mechanical  effect. 

Hence  to  change  the  speed  or  power  of 'a  mo- 
tor on  a  circuit  of  constant  potential,  the  speed 
or  power  is  increased  by  weakening  the  field, 
which  produces  a  decreased  counter-electro- 
motive force  and  an  increased  armature  current, 
and  consequently  the  increased,  mechanical 
effect  desired;  and  such  mechanical  effect  is  de- 
creased by  strengthening  the  field,  and  thus 
increasing  the  counter-electromotive  force. 

In  brief,  then,  Mr.  Sprague's  method  of  regu- 
lation consists  in  strengthening  the  magnetiz- 
ing effect  of  the  field-magnet  coils  of  the  motor 
to  decrease  the  mechanical  effects,  such  as 
speed  or  power,  or  both,  and  vice  versa,  weak- 
ening such  magnetizing  effect  to  increase  the 
mechanical  effects,  and  under  varying  loads 
the  speed  is  maintained  constant  by  an  inverse 
varying  of  the  strength  of  the  field  magnets. 

This  may  be  accomplished  in  two  ways,  one 
by  varying  the  field  circuits  by  a  mechanical 
governor  which  responds  to  any  variation  in 
the  speed  of  the  motor.  This,  however,  is  not 
satisfactory,  and  Mr.  Sprague's  ordinary  method 
of  working  is  to  make  use  of  certain  coils  in 
series  with  the  armature  and  dependent  upon 
it,  which  coils  have  a  resultant  magnet  action 
which  is  opposed  to  that  of  the  main  coils  of 
the  machine.  While  the  main  principle  is  the 
same,  Mr.  Sprague  has  a  number  of  different 
methods  of  applying  it.  The  first  has  a  series 
coil  in  series  with  the  armature,  and  its  action 
in  the  above  laws  will  be  understood  from  the 
following  description.  All  these  machines,  it 
should  be  said,  could  be  used  as  constant  speed 
machines  on  constant  current  circuits,  provided 
the  field  coils  are  properly  proportioned  for  the 


LATEST  AMERICAN   MOTORS  AND   MOTOR  SYSTEMS. 


161 


current  which  they  would  have  to  carry,  but 
with  certain  disadvantages,  as  will  be  shown. 

The  magnetic  moment  of  a  coil  may  be  de- 
fined as  the  product  of  the  amperes  flowing 
therein  by  the  number  of  turns,  and  if  the  main 
and  governing  coils  are  practically  similarly 
situated  with  regard  to  the  field-magnet  cores, 
the  magnetic  field  may  be  considered  as  pro- 
portional to  the  effective  magnetic  moment; 
that  is,  to  the  difference  of  the  magnetic  mo- 
ments of  the  shunt  and  series  field  coils,  so  long 
as  we  are  working  on  a  straight  or  nearly 
straight  line  characteristic.  This  characteristic 
can  be  determined  for  any  particular  cores  in 
any  of  the  well  known  ways;  for  instance,  by 
running  the  motor  as  a  dynamo  at  a  constant 
speed,  passing  variable  known  currents  through 
the  field  coils,  and  noting  the  potential  existing 
at  the  free  armature  terminals. 

For  a  properly  constructed  motor  the  field 
magnet  must  at  no  time  be  too  highly  saturated, 
that  is,  it  must  be  worked  with  a  characteristic 
which  is  a  straight  or  very  nearly  a  straight 
line. 

Let  /  denote  the  resistance  of  the  main  or 
shunt  field  coils;  m  the  number  of  turns  therein; 
r  the  resistance  of  the  differential  or  series  field 
coils,  and  n  the  number  of  turns;  E,  the  differ- 
ence of  potential  at  the  shunt  terminals;  e  the 
counter-electromotive  force  set  up  in  the  arma- 
ture; and  R  the  resistance  of  the  armature. 

E  —  e 

The  work  done  =  e  -       -  ;  that  is,  it  depends 
r 

upon  e,  a  variable  quantity,  and  upon  the  con- 
stants E  and  r. 

Now  e  varies  with  the  speed  and  field,  or  the 
effective  magnetic  moment  of  the  field,  but  the 
conditions  are  that  the  speed  remains  constant, 
hence  e  must  vary  with  the  field  alone. 

E 
Current  in  shunt  field  =  — ; 

E 
Magnetic  moment  of  same  =  m  — ; 


Current  in  series  field  = 


E  —  e 
E  +  r 


Magnetic  moment  of  same  =  n  - 


E—e 


The  effective  magnetic  moment  must  then  be 

E          E—e 

m n ;   and  the  conditions  are  such 

/  R  +  r 

that   (for  two  different   counter-electromotive 
forces  or  two  different  loads) 

E         E—e 

m n  — 

e  f  R  +  r 

e1  E          E—e1' 

m n 

/  R  +  r 

e       m  E  (R  +  r)  —  n  f  (E  —  e) 
or,  —  =  -  — ; 

e1      m  E  (R  +  r)  —  nf(E—  e1) 

e        m  E  (R  + r) —nf  E  +  nef 
or,  — -=-  -; 

e1       m  E  (R  +  r)  —nfE+  nelf 

or,  e  m  E  (R  +  r)  —  e  n  f  E  +  e  n  e1  f  =  e '  m  E 
(R  +  r)  —  e1nfE  +  e1  n  e  f. 

Cancelling  we  have  e  m  (R  +  r)  —  e  n  f  =  e1  m 
(R  +  r)  —  elnf, 

or,  m  (R  +  r)  (e  —  e1)  =  n  f  (e  — e1), 

m          f 
or,  —  =  -     — . 
n       R  +  r 

That  is  to  say,  the  number  of  turns  in  the 
shunt  coil  must  bear  the  same  ratio  to  the  num- 
ber in  the  series  coil  as  the  resistance  of  the 
shunt  coil  bears  to  the  sum  of  the  resistance  of 
the  series  coil  and  the  armature. 

This  is  the  Sprague  law  of  winding  for  a  ma- 
chine of  the  kind  mentioned,  and  so  wound  it 
will  be  self-regulating  for  any  constant  poten- 
tial up  to  the  maximum  allowed  by  the  con- 
struction of  the  machine,  and  from  no  load  up 
to  the  maximum. 

There  is  a  feature  of  motors  so  wound  which 
may  be  here  noticed. 

The  ratio  of  the  magnetic  moments  of  the 
shunt  and  series  fields  is 


m 


E 

f  mE  (R  +  r) 

-  or,  — . 

nf(E  —  e) 


E  —  e 


n 


R  +  r 


But 


R  +  r 
R  +  r       n 


f 


m 


162 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


m  En  E 

Hence  the  above  ratio  =  -  -  or, 


mn(E — e)      E  —  e 

That  is,  the  ratio  of  the  initial  to  the  effective 
electromotive  force  is  the  same  as  the  ratio  of 
the  moments  of  the  shunt  and  series  coil. 

E 
When  e  =  0  this  ratio  becomes  —  =1;  that 

E 

is,  the  moments  are  equal,  and  this  means  that, 
in  a  perfect  machine,  if  both  coils  be  closed  and 
in  their  normal  position,  for  any  potential  or 
current,  a  zero  field,  or  practically  so,  will  be 
formed,  and  the  motor  will  either  not  start  at 
all,  or,  if  it  does  start,  will  run  at  a  very  great 
speed,  take  the  maximum  current  at  any  given 
potential,  and  do  little  or  no  work  at  all. 

How  to  obviate  the  bad  effects  of  this  pecul- 
iarity, yet  to  take  advantage  of  it,  will  be 
shown  later. 

What  has  already  been  pointed  out  may  be 
again  stated,  that  the  motor  will  regulate  itself 
perfectly  for  all  potentials  so  long  as  we  work 
with  a  straight  line  characteristic,  but  it  must 
be  with  a  theoretical  efficiency  of  not  less  than 
fifty  per  cent.,  for  if  we  go  below  this,  the  gov- 
erning coil  works  in  the  wrong  direction. 

m  f 

Referring  to  the  equation  —  =  -      — ,  it  will 

n       R  -f  r 

be  seen  that  m  and  n  can  be  increased  in  the 
same"  ratio.  That  is,  if  means  are  provided 
for  varying  the  effective  magnetic  moments  of 
shunt  and  series  coils  the  motor  can  be  set  to 
run  at  different  determined  speeds.  It  is  evi- 
dent that  /  and  r  can  also  be  varied  to  change 
the  speed. 

Let  us  now  consider  the  same  class  of  motors 
with  constant  speed,  varying  load,  and  constant 
current. 

Let  the  resistances  and  turns  be  designated 
as  before.  Let  K  be  the  constant  current.  Let 
E  be  the  variable  potential  at  the  terminals  of 
the  motor  and  e  the  variable  counter-electromo- 
tive force. 

e(E—  e) 

The  work  done  = . 

R  +  r 

9 

We  must  eliminate  E,  making  it  dependent 
upon  e  and  the  constants  R,  r,  f,  and  K,  and 
hence  the  work  can  be  expressed  in  terms  of 
E,  r,  f,  K,  and  e,  of  which  e  is  the  only  varia- 


ble quantity;  e  depends  upon  speed  and  field,  but 
speed  is  constant.  Hence  our  conditions  re- 
quire that  with  the  same  current  we  make  e, 
and  hence  the  work,  variable,  but  by  changes 

in  the  field  alone. 

E 
Field  current  =  —  ; 


Armature  current  = 
E       E  —  e 


E  —  e 
-  —  . 
R+r 


or 


R+r  +  / 

Moment  of  shunt  field  =  m 


Moment  of  series  field  =  n 

Effective  moment  = 

m(R  +  r) 


f  K—  e 

/'       73       I        .      I      ^ 
R  +  ,  +J 

(R'+  r)K+  e 

R  +r  +f 
f  K  —  e 


R  +  r  +  f 


R  +  r+f 

Our  conditions  are  such  that 

e        m  (R  +  r)  K  +  me—n(fK  —  e) 


or,  e  m  (R  +  r)  K  +  m  e  e1  - 

e1  m(R  +  r)  K  +  mee1  —  nfKe1  +  nee1. 

Cancelling  and  transferring,  m  (R  +  r)  (e—  e1)  = 
nf(e  —  el); 

m  f 

or,  —  =  -      — , 

n       R  +  r 

which  is  the  same  law  as  found  for  constant 
potential. 


The  ratio  of  moments  is 


m  (R  +  r)  K  +  m  e 


When  e  =  0  this  becomes 
R  +  r        n 
m 


n  f  K  —  n  e 
m  (R  +  r) 


But 


hence  substituting  we  have 


m  n 


1. 


n  m 


LATEST  AMERICAN   MOTORS  AND   MOTOR  SYSTEMS. 

But  our  conditions  are  such  that 
f(E  —  e)  +  E  R 

f(E-, 


163 


That  is,  if  the  motor  is  at  rest  and  any  current 
is  sent  through  it  a  zero  field  will  be  produced. 
This  of  course  follows  from  what  has  been  al- 
ready said  about  the  constant  potential  motor. 

The  potential  E  which  will  exist  if  e  =  E  and 
no  current  is  passing  in  the  armature  is  /  K, 


E—r 


and  the  maximum  work  is  done  when  e  = 


2 


E  —  rC 

f 
E—rC—e 


R 
E  —  rC 

f 


=  shunt  current; 

armature  current; 
E  —  rC  —  e 


C; 


ER  —  rCR+f  E—rfC—ef=CRf; 
or,  C  Rf+r  f  C+  r  R  C=  fE  — ef  +  ER. 

/(#-< 
Whence  C  = 


Work  done  =  e 


fR+(f  +  R) 
E-rC—e 


R 


But  since  C  can  be  expressed  in  terms  of  e 
and  constants,  the  work  can  be  also  expressed 
in  terms  of  e  and  constants. 

E—r  C 
m-  -  =  shunt  current, 


E—rC 


m. 


f 


n  C  =  series  current; 
-  n  C  =  effective  current, 


E  —  r 


••m 


f(E  —  e)  +ER 
fR+(f+R)r 
~7~ 


f(E-e) 


m- 


fR+(f+R)r 
f 


f  R  +  (f  +  R)r 


E—r 


f  (E  —  el)+ER 


To  be  self-regulating,  the  motor  can  be  worked 
up  to  this  point,  but  not  beyond  it,  for  then  the 
regulating  coil  works  in  the  wrong  direction. 

In  another  variety  of  motor  this  series  coil  is     e 
placed  outside  the  terminals  of  the  shunt  coil. 
The  laws  governing  the  action  of  this  machine 
on  a  constant  potential  circuit  may  be  described 
as  follows: 

Let  the  same  letters  of  reference  be  used. 

Then  the  potential  existing  at  the  shunt  ter- 
minals will  be  E  =4  r  C. 


(f+R)r        f(E-e*) 
n  - 


(f+R)r 

mE  [f  R+  (f+R)r]  —mr  [f  (E—  e)  + 
m  E  [f  R  +  (f  +  R)  r]  —  m  r  [/  (E—el)  + 
ER]—nf[f(E—e)  +  ER] 
nf[f(E—el)   +  E  R}' 


or,  m  E  e  f  R  +  m  E  e  f  r  +  m  E  e  r  R  — 
m  e  r  f  E  +  m  e  r  f  e1  —  m  e  r  E  R  — 
e  n  f*  E  +  e  n  f"-  e1  -  -  e   n  f  E  R  = 
mE  e1  f  R  +  m  E  e1  f  r  +  m  E  e1  r  R  - 
in  e1  r  f  E  +  me1  r  f  e  -  -  m  e1  r  E  R  — 
e1  n  f"  E  +  elnf*e  —  e1  n  f  E  R. 

Cancelling  we  have — 

m  fR  (e  —  e1)  =  n  f-  (e  —  e1)  +  n  Rf  (e  —  e1); 

f+R 


in 

or,  —  = 
n 


R 


That  is,  the  number  of  turns  in  the  shunt 
main  field  bears  the  same  ratio  to  the  number 
of  turns  in  the  series  differential  field,  as  the 
sum  of  the  resistances  of  the  shunt  field  and 
the  armature  bears  to  the  resistance  of  the  ar- 
mature. 

This  is  the  Sprague  law  of  winding  for  a 
machine  of  this  character,  and  so  wound  the 
machine  will  be  self -regulating  for  any  constant 
potential  and  for  any  load  up  to  the  maximum 
allowed,  and  even  with  a  resistance  in  circuit 
and  with  varying  potential. 

The  same  peculiarity  exists  in  those  motors 
which  has  been  pointed  out  in  connection  with 
the  first  class  of  differentially  wound  motors, 
and  this  will  now  be  described. 

The  ratio  of  the  magnetic  moments  of  the 
shunt  and  series  fields  is. 


164 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


m  E  —  m  r 


f  (E—e)  +  ER 


f 


f 


nf  (E—e)  +  n  E  R 
fR+(f  +  R)r 

mE[fR  +  (f  +R)r]—m  r[f  (E—e)+E  R] 
or,  -  — . 

f[nf(E  —  e)  +  nER] 

If  e  —  0,  this  becomes 

m  Ef  R  +  m  Ef  r+mERr  —  mrfE  — 
mr  E  R 


f*nE  +fnER 
mR 


or, 


n(f 


m      f  +  R 

I  >l  I  I  • 

n          R 


Hence  the  ratio  becomes 


m  n 


1. 


n  m 


That  is  to  say,  if  a  motor  of  this  character  is 
at  rest  and  the  series  coil  in  its  normal  govern- 
ing position,  and  the  circuit  be  closed  to  the 
motor,  a  zero  field,  or  nearly  so,  will  be  pro- 
duced; for  under  these  circumstances  the  mag- 
netic moments  are  equal,  and  either  the  motor 
will  not  start  at  all,  or,  if  it  does  start,  will 
run  at  a  very  great  speed,  take  the  maximum 
current  at  any  given  potential,  and  do  little 
work  or  none  at  all. 

m       f  +  R 

Referring  to  the  equation  —  =  -       -  it  will 

n          R 

be  seen  that  m  and  f+R  can  be  increased  in 
the  same  ratio.  This  means  that  the  deter- 
mined constant  speed  of  the  motor  can  be  varied 
for  any  given  potential.  Also  m  and  n  can  be 
increased  in  the  same  ratio — that  is,  if  means 
are  provided  for  varying  the  effective  magnetic 
moments  of  shunt  and  series  coils,  the  motor 
can  be  set  to  run  at  different  determined 
speeds. 

This  motor  with  constant  speed,  varying  load, 
and  constant  current  will  now  be  considered. 

Let  the  turns,  resistance,  etc.,  be  designated 
as  before.  E  is  the  variable  potential  at  the 
terminals  of  the  shunt  field,  and  e  the  corre- 
sponding counter-electromotive  force. 


We  must  eliminate  E  and  express  the  work 
in  terms  of  e  and  constants;  e  depends  on  speed 
and  strength  of  field,  but  since  speed  is  con- 
stant e  depends  on  the  field  alone. 

E 
-  =  current  in  shunt  field, 

E  —  e 

—  =  current  in  armature, 

K  =  current  in  series  field; 

E       E—e 

and  therefore  K  =  —  + ; 

/         R 
whence  f  R  K  =  E  R  +  (E  —  e)  f ; 

E      R  K  +  e 
or,  —  = . 


m  R  K  +  m  e 


e  f+R 

The  conditions  are  —  =  - 


—  nK 


e1 


f+R 


n  K 


e        m  R  K  +  m  e  —  /  n  K  —  R  n  K 
or,  —  =  -  -j 

e1       mRK+m  e1  —  fnK—  Rn  K 

or,  e  m  R  K  +  m  e  e1  —  /  n  K  e  --  R  n  K  e  = 
e1  m  R  K+  in  e  e1  —  fn  K  e1  —  RnKe1: 


or,  (e  —  el) 


R  n  K; 

m       f+R 


l)  f  n  K  +  (e  —  e1) 


n          R 

This  is  the  same  law  of  winding  that  holds 
when  a  machine  of  the  same  class  is  used  for 
constant  potential;  and  the  same  remarks  in 
regard  to  the  zero  field  apply  as  in  the  former 
case. 

Also,  as  in  the  former  case,  the  speed  for  any 
given  current  can  be  varied  by  varying  the  re- 
sistance and  turns  or  the  effective  turns. 

From  the  foregoing  demonstrations,  it  fol- 
lows that  a  motor  of  either  class  depending  for 
its  regulation  on  this  differential  winding  will 
regulate  with  a  constant  current  only  when 
working  at  less  than  fifty  per  cent,  armature 
efficiency;  and  that  the  same  machine  with  the 
same  winding  will  regulate  on  a  constant  po- 


LATEST  AMERICAN   MOTORS  AND   MOTOR  SYSTEMS. 


165 


tential  circuit  only  when  working  at  over  fifty 
per  cent,  armature  efficiency. 

The  laws  above  set  forth  are  for  pure  electro- 
dynamic  motors;  if  there  is  any  permanent 
magnetism,  as  in  hard  cast  iron,  or  where  per- 
manent steel  magnets  are  used,  the  law  of  wind- 
ing is  modified  in  so  far  as  the  residual  or  per- 
manent magnetism  is  the  equivalent  of  an 
electro-magnetic  moment;  but  in  this  case,  too, 
there  should  exist  a  zero  field  if  the  governing 
coil  is  normally  closed  when  the  motor  is  at 
rest. 

The  fact  already  pointed  out,  that  in  the  best 
self-regulating  motor  there  is  a  zero  or  very 
weak  field  when  the  motor  is  started,  necessi- 
tates in  both  classes  of  motors,  especially  when 
it  is  desired  to  start  at  a  speed  not  greater  than 
the  normal,  or  when  there  is  any  load  on  the 
motor,  in  which  case  there  is  danger  of  burning 
out,  the  use  of  devices  whereby  the  action  of 
the  governing  coil  may  be  modified. 

This  may  be  done  by  the  introduction  of  a 
resistance,  by  shunting  the  coil  with  a  resistance 
or  by  the  variable  shunting  of  the  armature 
upon  the  main  field.  Mr.  Sprague,  however, 
prefers  to  use  a  switch  to  short-circuit  the  gov- 
erning coil  or  to  short-circuit  and  reverse  it.  If 
it  is  reversed,  then  the  first  rush  of  current 
makes  a  very  strong  field  instead  of  reducing 
it  to  zero  or  nearly  so,  increases  the  rotary 
effort  and  prevents  the  burning  out  of  the  ma- 
chine. 

As  an  instance,  if  a  constant  potential  motor 
has  the  series  coil  reversed  when  the  full  cir- 
cuit is  closed,  if  there  is  margin  enough  on  the 
field  characteristic  we  shall  have  a  field  twice 
as  strong  as  the  strongest  normal  field,  four 
times  the  strength  when  the  motor  is  doing  its 
maximum  work  per  unit  of  time,  and  a  mo- 
mentary rotary  effort  eight  times  that  existing 
when  the  maximum  work  is  on.  As  soon  as  the 
speed  comes  up,  the  governing  coil  is  short  cir- 
cuited and  then  reversed,  and  then  the  motor  is 
self-regulating. 

Having  obtained  a  machine  which  was  thus 
automatic,  Mr.  Sprague  made  another  step  in 
overcoming  the  distortion  or,  rather,  counter- 
acting the  distortion  set  up  by  the  armature, 
by  producing  a  distortion  in  the  field  magnets, 
which  is  dependent  on  precisely  the  same  cur- 
rent that  flowed  through  the  armature,  and  he 
uses  two  methods,  of  which  one  only  will  be 
described. 
21 


Main  field-magnet  coils  are  employed  in  shunt 
relation  to  the  armature,  differential  field-mag- 
net coils  in  series  with  the  armature,  and  addi- 
tional accumulative  field-magnet  coils,  also  in 
series  with  the  armature.  The  main  field  coils 
may  be  shunted  upon  the  armature  alone,  or 
upon  the  armature  and  both  the  cumulative 
and  differential  series  coils,  or  upon  the  arma- 
ture and  either  of  the  series  coils,  the  other 
series  coil  remaining  outside  the  terminal  of  the 
main  field  shunt. 

The  object  sought  is  to  maintain  the  non- 
sparking  points  of  the  commutator  cylinder 
constant  by  opposing  the  distortion  of  the  mag- 
netic field  due  to  variations  in  the  armature  cur- 
rent by  a  counter  distortion  dependent  upon 
such  variations,  whereby  the  magnetic  result- 
ant due  to  the  armature  and  field  magnet  is  un- 
changed, and  the  line  of  parallel  cutting  of  the 
lines  of  force  or  point  of  least  sparking  is  main- 
tained in  the  same  position. 

In  accomplishing  the  counter  distortion  of  the 
field,  the  motor  used  is  one  in  which  the  field- 
magnet  cores  extend  in  different  directions 
from  the  field  of  force  in  which  the  armature 
revolves.  The  differential  series  coils  are  wound 
or  arranged  so  that  their  greatest  effect  is  pro- 
duced on  diagonally  opposite  parts  of  the  mag- 
netic field ;  and  the  cumulative  series  coils, 
so  that  their  greatest  effect  is  produced  on  the 
other  diagonally  opposite  parts.  The  differ- 
ential coils  are  arranged  to  have  a  greater 
magnetizing  effect  than  the  cumulative  coils. 
A  decrease  of  load,  causing  a  decreased  arma- 
ture-current, tends  to  shift  the  magnetic  re- 
sultant of  the  armature  and  field  magnet; 
but  this  also  decreases  the  magnetizing  ef- 
fect of  all  the  series  coils,  and  therefore 
the  parts  of  the  field  principally  affected  by 
the  cumulative  coils  are  weakened,  and  those 
principally  affected  by  the  differential  coils  are 
strengthened,  whereby  a  distortion  of  field  is 
produced  opposed  to  that  produced  by  the  de- 
crease of  armature  current,  and  hence  the  mag- 
netic resultant — the  line  of  parallel  cutting  and 
the  points  of  least  sparking  —  remains  un- 
changed. Thus  no  shifting  of  the  commutator 
brushes  is  ever  required,  except  on  account  of 
wear. 

The  arrangement  of  two  sets  of  series  field 
coils — one  differential,  the  other  cumulative — 
may  be  employed  simply  as  a  means  of  field 
regulation  where  it  is  not  desired  to  produce 


166 


THE  ELECTRIC  MOTOR  AXD  ITS  APPLICATION 


the  counter  distortion.  In  such  case  the  coils 
may  be  evenly  wound  on  all  the  legs  of  the 
field  magnet  and  used  only  to  regulate  the 
motor,  being  wound  in  the  proportions  above 
stated.  The  differential  and  cumulative  series 
coils  have  a  differential  effect,  which,  as  the 
differential  coils  predominate  over  die  cumula- 
tive coils,  produces  a  weakening  of  the  total 
strength  of  the  field  magnet  when  the  armature 
current  increases,  and  a  strengthening  of  the 
field  magnet  when  the  armature  current  de- 
creases, and  so  maintains  constant  the  speed  of 
the  motor. 


cmtis 

but  in  this 


FIG.  1G6. — Sp*Ac.nt  Rucntic  MOTO*. 

One  of  Mr.  Sprague's  methods  for  varying 
the  speed  and  power  is  to  wind  the  field  mag- 
nets with  a  series  of  coils  of  different  cross 
section  and  resistance.  These  coils  are  all  in 
series  with  each  other,  and  the  bights  of  the 
coils  are  brought  to  a  commutator. 

In  the  simplest  form  of  this  motor,  one  end 
of  the  armature  circuit  is  connected  with  a 
contact  arm  arranged  to  travel  over  a  contact 
range,  thereby  making  electrical  connection 
with  different  sections  of  the  field  coils.  The 
other  end  of  the  armature  circuit  is  connected 
with  one  end  of  the  series  of  field  coils,  pre- 
ferably at  the  junction  of  such  series  with  the 
supplying  circuit.  As  the  arm  moves  over  the 
successive  contact*  the  armature  is  shunted 
around  a  greater  or  less  number  of  the  sections 
of  the  field  coils,  and  the  difference  of  poten- 
tial between  the  terminals  of  the  armature  cir- 


tions  to  the  next ; 
on  either  side,  and  so  on  till  the 
meet.  In  a  third  method  two  saiies 
£•  of  field-coil  sections  are  used,  and  the 
nights  connected  to  two  ranges  of  con- 
tact pieces  arranged  in  one  or  two  cir- 
cular or  partly  circular  sets.  Here.abo. 

two 

and  the  two; 

nab  of  the 

ture circuit  becomes  what  corresnomv  totiw 
galvanometer  circuit  in  the  Wbeatstone  bridge. 
As  the  arms  are  made  to  travel  over  the  suc- 
cessive contact  surfaces,  the  difference  of  po- 
tential existing  at  these  arms  or  at  the  terminals 
of  the  armature  circuit  decreases  from  the  max- 
imurn  to  aero,  changes,  and  increase  again  to 
the  maximum  reverse  potential 

In  this  last  arrangement  the  speed,  tormw, 
and  direction  of  rotation  can  be  varied  as  rap- 
idly as  desired  without  any  sparking  at  the  mo- 
ment of  reversal. 

In  tvpes  1  and  3  as  referred  to  above-  and  il- 
lustrated in  Fig.  l«*.  the  standard  mnthmea 
are  wound  in  the  sectional  method  described 
and  iu  addition  are  arranged  so  that  when  the 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTKMS. 


167 


motor  is  started  the  governing  coil  is  in  series 
with  the  armature  and  works  accumulatively, 
while  the  potential  at  the  armature  terminals 
is  progressively  raised  by  moving  along  the 
field  sections  by  means  of  the  commutator  at 
the  top,  part  of  tin;  field  sections  being  in  scries 
and  the  rest  in  shunt  with  the  armature;  this 
arrangement  gives  a  very  strong  rotary  torque; 
when  full  potential  has  been  reached,  the 
coarse  coils  are  short  circuited  and  then  re- 


up  to  the  maximum,  and  promptly  recover 
their  normal  speed  under  sudden  and  marked 
changes  in  load.  There  is  no  change  necessary 
in  the  lead  of  the  commutator  brushes. 

In  the  larger  type  of  machines,  however,  two 
forms  of  which  are  shown  in  Figs.  107,  I'JH,  and 
Hi!),  Mr.  Sprague  prefers  to  use  a  rheostat  for 
throwing  the  machines  into  circuit,  instead  of 
winding  the  field  coils  in  sections,  because  it 
is  a  much  cheaper  process  of  working,  and  as 


I-' It:.    Hi".   -  SrisAdfK    Kl.Kriinc   MOTOK. 


versed  and  the  machine  becomes  an  automatic 
machine,  having  the  following  qualities: 

It  can  be  thrown  into  a  circuit  at  a  dead 
rest  or  slow  speed,  without  any  disturbance  of 
potential  and  consequent  flickering  of  light. 
It  can  be  started  gradually,  whether  free  or 
under  full  load,  without  burning  of  brushes  or 
flickering  of  light,  the  potential  at  the  brushes 
being  raised  progressively  from  zero  to  maxi- 
mum. If  the  load  is  such  as  to  prevent  start- 
ing until  the  full  difference  of  potential  exists 
at  the  brushes,  the  motor  then  starts  with  a 
rotary  effort,  or  torque,  very  much  in  excess  of 
what  exists  under  the  condition  of  maximum 
work.  These  motors  are  perfectr>  automatic, 
running  at  nearly  the  same  speed  for  all  loads 


in  case  a  heavy  machine  should  be  damaged  in 
the  sectional  winding,  it  would  be  far  more 
costly  to  make  repairs  to  it  than  in  the  case 
where  a  rheostat  is  used.  Of  course  this  rheostat 
carries  no  current,  except  at  the  moment  of 
starting  tho  motor.  These  motors  will  lower  a 
varying  weight  at  the  same  speed  that  they 
will  pick  it  up,  and  with  the  same  freedom  from 
sparking. 

In  another  form,  a  variable  speed  machine, 
such  as  is  now  in  use  in  the  Western  Union  op- 
erating room,  the  rheostat  is  of  peculiar  con- 
struction. By  a  single  movement  of  the  switch 
the  machine  is  thrown  into  circuit  with  a  very 
strong  field,  the  potential  at  tho  armature  termi- 
nals is  gradually  raised,  and  after  full  potential 


168 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


has  been  reached  a  resistance  is  then  thrown 
into  the  field  magnet,  and  the  field  thus  weak- 
ened so  that  the  speed  of  the  machine  is  in- 
creased. This  method  of  working  allows  of  the 
finest  gradations  of  speed. 

Another  machine  which  is  just  being  brought 
out  for  use  on  constant  potential  circuits  per- 
mits of  nine  or  ten  variations  of  speed  from  a 
single  switch  movement  without  the  use  of  any 
external  rheostat,  and  another  type  permits  of 
a  like  variation  of  speed  and  entire  reversal  of 
movement,  also  with  the  single  switch.  This 
latter  type  is  designed  for  operation  -on  street 
cars. 


FIG.  168. — SPRAGUE  ELECTRIC  MOTOR. 


For  all  ordinary  work  motors  are  built  for 
constant  potential  circuits  of  about  100  volts. 
But  the  demand  has  come  for  220  volt  machines 
to  go  on  the  Edison  three-wire  circuits.  Before 
long  the  Sprague  Company  expect  to  undertake 
some  special  cases  of  transmission  of  power  in 
connection  with  mining  work  which  involve 
the  transmission  of  very  large  powers  over  long 
distances  and  under  high  pressure,  such  as  200 
horse  power  sixteen  miles  with  1,000  volts  at 
the  motors,  the  entire  electrical  conditions  being 
perfectly  automatic,  both  at  the  generating  and 
receiving  end.  A  very  large  number  of  special 
problems  are  now  being  considered  and  motors 
are  about  to  be  used  where  none  but  the  most 
enthusiastic  believers  in  their  adaptability  will 
believe  it  possible. 

Among  the  very  interesting  facts  which  have 
been  brought  out  by  experience  is  this,  that  on 
all  ordinary  classes  of  work  motors  do  not 


average  over  thirty-five  to  forty  per  cent,  of  the 
maximum  capacity  which  may  be  safely  de- 
manded of  them.  A  central  station  hence  can 
take  advantage  of  this  falling  off  of  work,  and 
since  there  is  an  actual  recovery  of  about 
sixty-five  per  cent.,  and  this  sixty -five  per  cent, 
is  only  about  forty  per  cent,  of  the  capacity  of 
the  motors  which  are  in  operation,  it  follows 
that,  for  every  100  horse  power  in  a  steam  en- 
gine at  a  central  station,  including  ten  per 
cent,  loss  on  distribution  where  the  work  is 
widely  distributed,  about  170  horse  power  can 
actually  be  contracted  for. 

We  come  next  to  Mr.  Sprague's  work  in  con- 
nection with  electric  railways.  In  December  of 
1885,  a  paper  was  read  before  the  Society  of 
Arts,  Boston,  by  Mr.  Sprague,  on  the  subject  of 
the  application  of  electricity  to  the  propulsion 
of  motors  on  the  elevated  railroads  of  New 
York?  This  paper  was  an  elaborate  technical 
article  which  made  a  thorough  investigation  of 
the  power  used  and  its  distribution,  and  indi- 
cated some  of  the  methods  which  the  writer 
proposed  fo  carry  out  in  the  system  that  he  had 
devised.  The  Third  Avenue  Elevated  Road  was 
taken  as  an  example.  It  was  shown  that  on 
this  road  the  work  was  expended  in  three  dif- 
ferent ways,  viz. : 

1.  In  overcoming  the   inertia  of  the  train, 
which  was  fifty-nine  per  cent,  of  the  total. 

2.  In  lifting  the  train  on  up  grades,  which 
amounted  to  twenty-four  per  cent. 

3.  In  traction,  seventeen  per  cent. 

It  was  pointed  out  that  because  of  the  great 
frequency  of  stoppages  and  the  necessity  of 
high  speeds  on  this  road,  most  of  the  energy 
of  the  train  which  was  put  into  it  on  getting 
under  way  and  lifting  it  on  up  grades  was  of 
little  value  for  traction.  At  the  time  the  paper 
was  written,  there  were  at  commission  hours 
sixty-three  trains  in  operation  at  one  time  on 
the  up  and  down  tracks.  This  was  on  a  double 
track  line  of  only  eight  and  one-half  miles 
length.  The  aggregate  power  that  the  engines 
on  this  road  were  capable  of  exerting  was 
nearly  11,700  horses,  the  engines  being  of  about 
185  horse-power  capacity.  The  average  power 
exerted  during  the  time  trains  were  in  motion 
was  4,040  horses,  or,  for  the  entire  time  on  a  trip, 
including  stoppages,  about  seventy-four  horses 
for  each  train  of  four  cars. 

The  problem  of  how  to  handle  this  tremen- 
dous power  on  grades  running  up  as  high  as 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


169 


105  feet  to  the  mile,  with  trains  stopping  every 
third  of  a  mile,  and  sometimes  not  half  a  station 
apart,  and  sometimes  reaching  a  speed  of 
twenty  to  twenty-two  miles  an  hour,  is  no  mean 
one.  It  is  true  that  small  roads  have  been  op- 
erated, among  them  one  six  miles  long  at 
Portrush,  Ireland,  but  the  conditions  are  totally 
different,  and  the  demands  which  would  be 
made  upon  an  electrical  system  by  the  condi- 
tions of  service  on  the  elevated  railroads  pre- 
sent a  new  problem,  and  this  problem  not  alone 
an  electrical  but  also  a  mechanical  one. 


The  great  amount  of  power  which  is  used  on 
the  elevated  railroads  and  the  distance  over 
which  the  trains  are  hauled  necessitate  in  the 
electric  circuit  large  currents  of  a  high  poten- 
tial. The  potential  decided  on  was  600  volts, 
and  the  experiments  on  the  Thirty-fourth  street 
section  have  been  carried  on  with  that  pressure. 
No  such  electrical  potential  has  ever  been  used 
in  practice  for  this  kind  of  work.  The  occasion 
for  it  has  not  existed,  and  motors  which  might 
be  used  with  small  powers  over  short  distances 
and  with  low  potentials  would  not  avail  there. 


FIG.  109. — SPRAGUE  ELECTRIC  MOTOR. 


The  elevated  system  presents  the  result  of  a 
great  many  years  of  careful  thought  in  en- 
gineering study.  It  is  the  culmination  of  a 
great  many  improvements.  It  has  been  car- 
ried to  a  degree  of  efficiency  far  higher  than  its 
most  earnest  supporter  thought  possible.  It 
has  been  taxed  to  its  uttermost.  Recognizing 
these  difficulties,  Mr.  Sprague  has  been  for  a 
long  time  engaged  in  the  elaboration  of  a  sys- 
tem which  for  some  months  past  has  teen  in  ex- 
perimental operation  on  the  north  track  of  the 
Thirty-fourth  street  branch  of  the  Manhattan 
Railroad.  Car  No.  203,  a  full-sized  standard 
passenger  car  of  the  elevated  railroad,  was 
placed  at  his  disposal  by  the  officers  of  the  Man- 
hattan Company,  and  this  has  been  equipped 
and  -is  now  a  thorough-going  experimental  car 
in  which  a  great  many  problems  are  being 
worked  out. 


Some  idea  of  the  current  and  potential  neces- 
sary for  operating  the  Third  avenue  line  may 
be  easily  gathered  from  the  following  facts. 

As  mentioned  above,  there  are  at  one  time 
4,040  horse  power  actually  being  developed. 
With  an  efficiency  of  eighty  per  cent,  for  the 
motors,  this  would  mean  a  current  of  43,291 
amperes  if  one  hundred  volts  were  maintained 
at  the  terminals  of  the  motors.  With  600  volts 
this  would  be  reduced  to  7,215  amperes.  The 
handling  of  a  current  of  7,215  amperes  and  of 
from  600  to  065  volts  electromotive  force  is  a 
somewhat  difficult  matter.  A  conductor  to 
carry  this  amount  of  energy  without  a  very 
large  loss  under  ordinary  conditions  must  be 
large,  but  with  the  stations  properly  put  in  and 
with  the  rails  properly  reinforced,  together 
with  the  methods  of  working  which  will  be 
described  more  in  particular  below,  it  will  be 


170 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


seen  that  the  difficulty  of  handling  this  has 
been  very  largely  reduced.  We  will  now  enter 
into  a  somewhat  detailed  description  of  this 
system,  both  with  regard  to  what  is  being 
done  and  what  will  probably  be  done  in  the 
future. 

The  first  subject  to  be  considered  is  the  gen- 
erating station.  The  system  preferred  by  Mr. 
Sprague  is  the  operation  of  a  number  of  dyn- 
amos wound  so  as  to  generate  at  their  normal 
speed  and  with  a  full  load  an  electromotive 
force  of  about  G70  volts  at  their  terminals. 
These  dynamos  are  wound  for  constant  poten- 
tial circuits.  They  are  of  very  low  armature 
resistance,  and  have  high-resistance  shunt 
fields.  The  dynamos  may  be  built  so  as  to 
maintain  a  constant  potential  under  all  loads 
at  the  junction  of  the  mains  with  the  track. 
There  is  one  disadvantage,  however,  about  this, 
and  that  is,  if  the  electromotive  force  of  the 
dynamos  rises  automatically,  and  there  should 
be  any  very  serious  cross  on  the  line,  the  ma- 
chines might  be  burned  out.  Where  they  are 
wound  with  the  field  magnets  in  a  simple 
shunt  circuit,  and  no  cumulative  coil  in  series 
with  the  armature,  any  very  bad  cross  on  a 
line  will  lower  the  potential  at  the  terminals 
of  the  machines,  and  while  a  very  heavy  load 
will  come  upon  them  for  a  brief  interval  of 
time,  the  drop  of  potential  at  the  terminals 
will  be  sufficient  to  so  far  demagnetize  the  field 
magnets  that  the  machines  cannot  be  burnt 
out.  In  addition,  however,  to  the  ordinary 
shunt  coil,  Mr,  Sprague  employs  a  special  wind- 
ing, one  which  now  appears  in  his  railroad  mo- 
tors. This  special  winding  is  a  coil  in  series 
with  the  armature,  whose  polarity  is  exactly  at 
right  angles  to  the  polarity  set  up  by  the  shunt 
coils,  and  is  so  proportioned  that  it  automatically 
maintains  the  point  of  non-sparking  coincident 
with  the  line  of  contact  with  the  brushes  on 
the  commutators.  This  series  coil  would  not 
have  the  effect  of  an  ordinary  cumulative  coil. 
It  would  not  raise  the  potential  of  the  dynamos, 
but  simply  makes  them  non-sparking  with 
fixed  brushes  under  all  loads. 

Considering  the  length  of  road  and  the 
amount  of  power  used  it  would  be  better  to 
have  two  central  stations  instead  of  one. 
These  stations  would  be  of  the  most  improved 
possible  mechanical  construction.  The  engines 
would  be  compound,  condensing,  and  placed 
near  the  water.  By  this  means  the  coal  con- 


sumption could  be  reduced  at  the  central  station 
to  as  low  as  two  pounds  of  coal  per  indicated 
horse  power.  By  having  two  stations,  each  re- 
moved about  a  quarter  of  the  distance  of  the 
length  of  the  road  from  either  end,  the  size  of 
conductor  which  is  necessary  for  the  middle 
rail  is  only  one-fourth  that  which  would  be  re- 
quired were  there  only  one  station  in  the  mid- 
dle. Furthermore,  the  points  of  supply  of 
current  from  each  station  should  be  maintained 
at  the  same  differences  of  potential,  to  obtain 
which  Mr.  Sprague  runs  an  independent  line  wire 
from  station  to  station,  with  suitable  indicators 
in  it,  showing  whenever  there  is  any  inequality 
of  potential  existing  at  the  supply  points.  This 
is  done  because  the  highest  possible  economy 
requires  perfectly  equal  differences  of  potential 
at  all  points  of  supply,  no  matter  how  many 
the  trains,  nor  where  they  may  be  situated  on 
the  track.  The  combined  capacity  of  the  two 
stations  would  be  something  more  than  equal 
to  the  highest  total  horse  power  appearing  at 
any  one  time  on  the  road,  which,  as  we  have 
seen,  is  about  4,700  horse  power.  It  will  be 
noted  that  there  are  no  losses  allowed  for  here. 
Why  this  is  so  will  be  explained  in  describing 
the  system  of  braking  which  is  used.  This, 
then,  would  give  a  capacity  at  each  station  of 
about  2,500  horse  power.  On  account  of  the 
rise  and  fall  of  the  work  done  on  the  line,  it 
being  light  at  night,  somewhat  heavier  during 
the  middle  of  the  day,  and  at  its  maximum 
during  the  morning  and  evening,  this  2,500 
horse  power  would  be  divided  up  into  about 
four  units,  and  to  allow  for  any  break-down  of 
an  engine  these  units  would  be  of  about  800 
horse  power  each.  The  travel  on  the  road  is  so 
perfectly  known,  and  follows  such  a  well-de- 
fined law  of  increase  and  decrease,  that  there 
would  be  no  difficulty  whatsoever  in  starting 
the  engines  at  the  proper  time  and  throwing 
the  dynamos  into  circuit.  This  system  of  power 
generation  would  be  the  most  economical  possi- 
ble. With  improved  boilers  and  improved 
methods  of  burning  cheap  fuels,  and  with  high 
grades  of  engines,  compounding  and  condens- 
ing, results  would  be  obtained  which  would  be 
very  gratifying. 

We  come  now  to  the  system  of  distribution, 
and  this  will  be  described  more  particularly 
with  regard  to  the  demands  of  the  elevated 
railroads,  leaving  out  particular  reference  to 
street  roads,  which  form  a  department  by  them- 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


171 


selves.  There  are  many  things  which  pertain 
to  this  system  of  distribution  which  would,  of 
course,  appertain  to  street  work.  The  main 
rails  are  grounded,  and  form  one  side  of  the 
circuit,  being  connected  to  the  structure  of  the 
road  at  suitable  intervals.  Four  single  rails, 
together  with  the  superstructure  and  the  ground 
connections,  form  a  path  of  very  low  resist- 
ance, and  there  would  probably  be  no  need  of 
any  reinforcement  at  the  fish-plates.  Should 
such  reinforcement  be  found  to  be  advisable,  a 
short  connecting  piece  would  be  made  from  one 
rail  to  another,  very  much  in  the  same  manner 
as  is  now  done  where  the  track  is  used  for  elec- 
tric signals,  or,  as  with  the  middle  rail,  a  main 
conductor  would  be  used.  The  other  part  of 
the  circuit  consists  of  a  very  light  rail  of  special 
construction,  thoroughly  well  insulated  in  a 
simple  manner,  and  raised  so  that  its  top  is 
from  three  to  four  inches  above  the  plane  of  the 
ordinary  traffic  rails.  This  rail  is  not  continu- 
ous, being  of  necessity  broken  at  all  switches, 
turn-outs,  sidings,  and  cross-overs.  The  ends 
terminate  about  eighteen  inches  from  all  cross- 
ing traffic  rails,  and  instead  of  ending  abruptly, 
they  are  bent  down  slightly,  so  that  when  the 
collecting  wheels,  running  on  the  central  rail, 
leave  or  enter  them,  they  do  so  without  any 
shock  or  jar  to  the  spring  mechanism  which 
carries  them.  This  middle  rail  is  further  divided 
up  into  sections  of  any  convenient  length  de- 
sired, say  at  intervals  of  500  or  600  feet. 

In  addition  to  this  middle  rail,  there  extends 
along  the  entire  length  of  the  line  a  heavy, 
continuous  conductor,  thoroughly  insulated. 
This  is  connected  to  both  ends  of  each  section 
by  fusible  plugs  or  cut-outs  and  a  short  branch 
circuit.  The  branch  circuits  of  the  cut-outs 
form  a  Y  connection,  the  main  conductor  being 
secured  to  the  stem  of  the  Y  and  one  end  of 
each  section  to  the  arms  of  the  Y.  It  will  be 
seen  now  that  in  the  normal  condition  of  af- 
fairs if  current  is  flowing  from  one  part  of  the 
road  to  another  part  and  there  is  no  train  be- 
tween these  two  parts,  that  this  current  is  car- 
ried over  a  double  ladder-like  circuit.  The  main 
conductor  carries  the  major  part  of  the  current 
and  the  sectional  working  conductors  a  smaller 
part.  So  long  as  there  is  no  train  on  the  sec- 
tions adjacent  to  any  connection,  it  is  evident 
that  there  is  no  difference  of  potential  existing 
at  the  two  opposite  ends  of  the  connecting 
branch,  and  no  current  will  flow  over  it,  al- 


though very  powerful  currents  are  flowing  past 
each  end  of  it.  These  currents  will,  of  course, 
be  in  the  same  direction.  When,  however,  a 
train  enters  a  section  it  does  not  make  any  con- 
tact whatever  with  the  main  continuous  con- 
ductors, but  only  with  the  working  conductor, 
and  current  is  supplied  to  this  working  con- 
ductor from  both  ends,  partially,  it  may  be, 
through  the  working  conductors  next  adjacent, 
but  mainly  through  the  branches  connecting  it 
to  the  main  conductor;  that  is,  there  is  a  dif- 
ference of  potential  set  up  in  the  different 
parts  of  this  circuit,  and  parts  which  were  inert 
before  become  active  the  moment  a  train  passes 
on  to  a  section,  no  matter  whether  the  train  be 
taking  current  from  the  line  or  giving  it  to  it. 
The  current  that  flows  through  these  branches 
may  be  made  to  actuate  any  kind  of  special  de- 
vice which  is  necessary,  and  thus  forms  a  per- 
fect block  system  of  signalling,  which  operates 
by  the  presence  of  a  train  upon  a  section,  since 
this  train  automatically  sets  signals  at  both 
ends  of  its  section.  These  signals  are  of  a  va- 
riety of  kinds,  visual  or  audible,  or  both.  Some 
are  day  and  some  night  signals;  and  the  incan- 
descent lamp,  preferably  two  or  more  in  multi- 
ple circuit  with  each  other,  are  used  for  the 
night  signals.  Since  the  current  on  a  motor  is 
under  perfect  control,  it  follows  that  even  if  the 
train  is  at  rest  on  the  section,  the  engineer  is 
able  to  set  his  signals. 

One  of  the  great  advantages  of  this  system 
of  main  and  working  conductors  is  this:  If 
there  is  any  bad  cross  or  accident  on  the  line 
the  section  will  be  cut  out.  The  rest  of  the 
road  will  not  be  interfered  with  in  the  slightest, 
but  the  whole  circuit  will  remain  intact  with 
the  exception  of  the  one  particular  branch  of 
500  or  600  feet,  which  has  been  affected.  The 
signals  may  be  made  of  that  automatic  charac- 
ter such  that  when  a  cross  does  occur  sufficient 
to  break  the  safety  catches  of  that  particular  sec- 
tion a  signal  is  set  and  cannot  be  replaced  until 
the  section  is  repaired.  We  have  here  a  per- 
fect safeguard  against  any  extended  disabling 
of  the  line.  Furthermore,  if  it  becomes  desira- 
ble at  any  time  to  operate  a  signal  at  only  one 
end  of  the  section,  the  other  end  of  the  section 
can  be  cut  out.  If  repairs  are  made,  a  section 
of  the  road  being  taken  out  or  replaced,  the 
track  foreman  can  at  once  cut  that  particular 
section  out  of  circuit,  and  after  his  repairs  are 
made  put  it  in  again  without  interfering  with 


172 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


the  main  line.  In  addition  to  these  devices, 
the  main  working  conductor  can  be  divided  up 
into  sections  and  switches  inserted,  so  that  if  it 
be  desirable  to  cut  out  any  extended  portion 
of  the  track  in  case  of  any  accident  which 
makes  the  passage  over  a  section  of  the  track 
inadvisable,  as  in  case  of  a  fire,  that  portion 
can  be  cut  out  without  the  necessity  of  discon- 
necting each  individual  section. 

In  addition  to  these  arrangements,  the  con- 
ductors of  like  potentials  on  different  tracks 
and  switches  are  connected  by  cross  circuits 
which  tend  to  equalize  the  potentials  on  the 


We  now  come  to  the  question  of  motor  con- 
struction. The  elevated  railroad  presents  a 
special  problem,  as  the  strength  of  the  super- 
structure is  limited.  At  present  the  trains  are 
drawn  by  locomotives  which  aggregate  about 
twenty-two  and  a  half  tons  in  weight.  Of  this 
weight  only  fifteen  tons  is  available  for  trac- 
tion, this  being  the  weight  on  the  drivers.  The 
weight  of  twenty -two  and  a  half  tons  is  cen- 
tred in  a  very  small  space.  Immediately  be- 
hind the  locomotive  is  the  forward  truck  of  a 
car  with  a  proportionate  weight  of  nearly  nine 
tons.  There  is  then  a  total  weight  of  over 


FIG.  170. — SPRAGUE  ELECTRIC  RAILWAY  SYSTEM — ONE-CAR  TRAIN. 


line,  especially  where  there  are  any  bad  joints 
in  the  rail,  and  also  when  one  track  is  more 
heavily  loaded  than  the  other.  Another  great 
advantage  of  these  cross  connections  is  that 
the  current  generated  by  trains  running  on 
down  grades  and  stopping,  can  not  only  be  sent 
back  to  the  conductor  on  its  own  particular 
track  and  circulate  through  the  system,  but  it 
can  take  a  shorter  and  more  direct  path  to  the 
opposite  track  where  a  train  may  be  moving  on 
the  up  grade  or  just  starting.  It  should  be 
further  stated  that  both  tracks  are  supplied 
from  the  same  source,  forming  one  complete 
circulating  system.  All  motors  are  run  in  par- 
allel circuit  with  each  other,  the  current  in  each 
being  independent  of  the  current  in  all  others, 
and  the  motors  on  the  one  track  are  in  parallel 
circuit  with  the  motors  on  the  other. 


thirty-one  tons  in  a  space  of  about  thirty-six 
feet,  which  is  less  than  the  distance  between 
two  columns.  The  consequence  is  that  the 
strains,  both  tensile  and  shearing,  are  very 
great;  but  these  strains  are  not  the  only  source 
of  danger.  The  vibration  set  up  by  a  moving 
train,  both  vertical,  due  to  the  weight,  and 
longitudinal,  due  to  the  motion  of  the  train,  has 
a  shattering  effect  which  is  very  great.  It 
tends  to  loosen  the  bolts  and  badly  strains  the 
whole  structure.  There  is  an  additional  vibra- 
tion due  to  the  reciprocal  strokes  of  the  steam 
locomotive  and  its  consequent  unevenness  of 
pull.  If  an  electric  locomotive  were  applied  to 
handle  a  train,  and  it  were  made  of  fifteen  tons 
weight,  it  would  pull  more  than  a  steam  locomo- 
tive of  equal  weight,  since  all  of  it  could  be 
put  upon  the  driving  wheels,  and  there  would 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


173 


be  no  necessity  of  additional  truck  wheels.  But 
a  fifteen-ton  electric  locomotive  properly  con- 
structed and  handled  would  pull  even  more 
than  a  twenty-two  and  a  half  ton  steam  loco- 
motive with  fifteen  tons  on  its  drivers.  If  the 
weight  was  distributed  on  four  wheels,  the 
wheels  being  on  two  perfectly  independent 
axles,  there  would  be  absolutely  equal  pressure 
on  each.  This,  however,  is  not  the  case  with  a 
steam  locomotive.  In  addition  to  this,  the 
strain  could  be  simultaneously  brought  on  all 
the  wheels  of  an  electric  locomotive  with  such 
a  perfect  progression  that  they  would  adhere  to 
the  rail  more  firmly  than  an  equal  weight 


This  is  the  manner  in  which  a  single  car  is 
now  being  operated  on  the  Thirty-fourth  street 
branch  of  the  Third  Avenue  Elevated  Railroad 
in  New  York  city.  The  accompanying  illus- 
trations, Figs.  170,  171,  and  172,  show  the  car 
in  one  and  two  unit  combination,  and  in  end 
view,  as  it  appears  upon  the  track.  The  truck 
upon  which  the  car  is  mounted  is  shown  in 
perspective  in  Fig.  173,  and  in  detail  plan  and 
elevation  in  Figs.  174  and  174  a. 

As  will  be  seen,  the  latter  represent  a  stand- 
ard iron  truck  such  as  is  in  use  on  all  the  new 
cars  of  the  elevated  railroad,  with,  of  course, 
some  omissions  and  changes  which  were  neces- 


Fio.  171. — SPEAOCI  ELECTRIC  RAILWAY  SYSTEM — Two-CAU  TRAIN. 


where  the  motion  is  derived  from  a  reciprocal 
movement.  Furthermore,  there  is  a  certain 
amount  of  increased  adhesion  of  the  wheels, 
just  how  much  it  is  impossible  to  say,  because 
it  varies  under  different  conditions,  and  this  is 
probably  due  to  the  heating  effect  of  the  cur- 
rent passing  from  the  rail  into  the  wheel. 

Another  method  of  handling  the  cars,  and 
this  is  the  most  logical,  although  it  may  be  a 
somewhat  more  costly  method  of  working  when 
dealing  with  old  rolling  stock,  is  the  placing  of 
the  motors  underneath  the  cars  on  the  trucks 
which  carry  them.  In  this  way  at  least  one- 
half  of  the  weight  of  the  car  and  the  passengers, 
as  well  as  the  motors,  is  available  for  traction. 

If  the  motors  are  thus  placed  under  the  cars, 
each  can  be  made  an  independent  unit,  or  a 
dozen  cars  can  be  operated  in  a  single  train  by 
a  small  regulating  truck  placed  ahead  of  them. 

22 


sary  for  attaching  the  motors.  The  principal 
omission  is  that  of  all  braking  apparatus. 
There  are  two  motors  carried  on  this  truck, 
each  in  the  space  between  the  axle  and  the 
centre  cross-piece.  The  field  magnets,  which 
are  made  of  the  finest  selected  scrap  wrought 
iron,  are  built  up  of  four  segments,  all  forming 
parts  of  circles.  Two  of  these  form  the  pole 
pieces  and  to  these  are  attached  heavy  bronze 
hangers.  The  latter  carry  the  armature,  which 
is  wound  on  a  special  modification  of  the  Sie- 
mens system,  and  has  at  each  end  forged  steel 
pinions  of  three  inches  face,  and  3.7  inches 
diameter  on  the  pitch  line.  There  are  thirteen 
teeth  only.  The  hangers  are  extended  and  em- 
brace the  axle,  which  is  turned  off  to  a  perfectly 
smooth  surface,  leaving  a  small  shoulder  at 
each  side.  Part  of  the  hangers  extending  from 
the  magnet  pole  pieces  embrace  one-half  of  the 


174 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


axle,  and  the  opposite  half  is  embraced  by 
heavy  bronze  caps,  and  inside  each  there  are 
split  liners  to  take  up  the  wear.  The  armature 
shaft,  as  it  passes  through  the  hanger,  is  car- 
ried by  two  curved  self -concentrating  sleeves. 

On  the  axles,  close  to  the  hub  of  the  wheels 
on  each  side,  are  two  split  gears.  These  differ 
in  character.  One  is  keyed  and  bolted  directly 
on  to  the  axle,  which  is  first  turned  off,  and  is 


FIG.  172.— END  VIEW  OF  CAR. 


a  fixture.  The  other  is  composed  of  four  parts, 
two  being  inner  webs  which  are  keyed  on  to 
the  axle;  the  two  outer  ones  form  the  geared 
section  and  are  bolted  together  and  have  cor- 
responding webs  projecting  inwardly,  and  fit 
snugly  both  on  the  outer  edge  and  on  the  face 
of  the  webs  which  are  keyed  to  the  axle.  The 
outer  and  inner  webs  are  held  together  par- 
tially by  the  method  in  which  they  are  turned 
up,  but  principally  by  bolts  passing  through 
them  which  work  in  curved  slots.  These,  then, 
constitute  adjustable  split  gears,  and  are  prob- 
ably a  new  thing  in  mechanics.  The  gear 
wheels  are  of  an  especially  fine  grade  of  cast 
iron,  and  are  of  the  same  face  as  the  pinions 
which  mesh  into  them.  The  number  of  teeth 


in  these  gears  is  sixty-six;  they  are  of  the  in- 
volute cut,  so  that  if  the  motor  should  be  moved 
to  or  from  the  axles  slightly,  the  gears  will  still 
run  perfectly  true,  with  only  a  little  more  or 
less  closeness  of  meshing.  The  pinions  on  the 
armature  shaft  are  set  so  that  the  one  is  half  a 
tooth  in  advance  of  the  other.  Ordinarily,  it 
would  be  a  very  difficult  matter  to  get  the 
splines  on  both  the  armature  shaft  and  the  axle 
and  in  the  pinion  and  gears  so  that  they  would 
mesh  smoothly  when  running  forward  and 
backward,  and  it  was  for  the  purpose  of  getting 
rid  of  this  trouble  that  the  adjustable  split  gear 
was  designed.  It  is  now  only  necessary  to  key 
the  two  pinions,  one  fixed  gear,  and  the  web  of 
the  other  gear  in  position  without  any  regard 
to  their  meshing.  The  motor  is  then  swung 
into  position,  the  hangers  made  to  engage  the 
axle,  the  caps  are  put  on,  and  the  motor  being 
moved  forward  and  backward  two  or  three 
times  while  the  bolts  of  the  adjustable  gear  are 
slack,  this  gear  will  assume  a  perfectly  correct 
position.  The  bolts  are  now  tightened  up  and 
there  is  thus  a  nest  of  double  pinions  and 
double  gears  all  meshing  with  absolute  preci- 
sion, no  matter  whether  the  motor  runs  back- 
ward or  forward.  The  method  of  mounting 
produces  a  concentric  motion,  and  by  this 
means  the  driving  and  the  driven  axles  are 
maintained  absolutely  parallel  in  two  planes 
under  all  circumstances. 

To  allow  the  motor  freedom  to  follow  all  the 
movements  of  the  independent  axles  over  frogs 
and  switches,  and  also  for  taking  part  of  the 
weight  of  the  motor  off  the  body  of  the  axles 
and  to  throw  it  on  to  the  boxes,  one  end  of  the 
motor  is  suspended  at  its  centre  by  a  bolt  pass- 
ing through  the  cross  girders.  This  bolt  is  ad- 
justable, and  the  upper  part  is  held  by  a  very 
stiff  spring  in  a  state  of  compression,  which 
spring  is  in  turn  supported  by  a  wrought-iron 
saddle.  The  motor  is  then,  so  to  speak,  weighed 
or  flexibly  supported  from  the  body  of  the 
truck.  There  is  also  a  smaller  spring  to  take 
up  any  back  movement  or  tendency  to  lift  of 
the  motor.  This  suspension  is  directly  in  the 
centre  of  the  pole  piece,  and  the  field  magnets, 
which  are  grooved  in  the  form  of  a  circle,  are 
independently  detached  from  the  pole  pieces, 
one  of  them  being  put  on  after  the  motor  is 
in  place. 

Because  of  the  relation  between  the  teeth  in 
the  pinion  and  the  split  gear,  it  is  necessary  for 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


175 


the  armature  shaft  to  make  sixty-six  revolu- 
tions before  the  teeth  engage  in  the  same  way, 
and  each  tooth  of  the  pinion  must  in  turn  en- 
gage every  tooth  in  the  gears.  It  will  be  seen 
also,  since  the  motor  is  suspended  at  one  end 
by  the  truck  axle  and  at  the  other  by  com- 
pression springs  operating  in  both  directions, 
that  whenever  the  axle  is  in  motion  there  is 
always  a  spring  touch,  so  to  speak,  of  the  pin- 
ions upon  the  gears.  Barring  friction,  a  single 
pound  of  pressure  exerted  in  either  direction 
will  lift  or  depress  the  motor  a  slight  amount. 


1,500  to  2,000  pounds  upon  each  gear.  Strain 
has  also  been  put  upon  these  gears  as  sud- 
denly as  it  is  possible  to  close  a  circuit  across 
600  volts,  and  without  injurious  effect. 

This  method  of  mounting  motors  tends  to 
produce  an  absolutely  perfect  form  of  gear,  and 
has  practically  obviated  the  noise  which  was  at 
first  anticipated. 

Designs  for  motors  of  from  200  to  300  horse 
power  mounted  on  these  same  principles  will 
soon  be  finished,  and  the  motors  constructed 
and  put  into  operation. 


FIG.  173. — TRUCK  OF  SPKAGUE  CAR. 


It  follows  that  no  matter  how  sudden  a  strain, 
nor  how  great,  it  is  impossible  to  strip  the 
gears  unless  the  resultant  strain  is  greater  than 
that  of  the  tensile  strength  of  the  iron;  be- 
cause the  moment  that  the  motor  exerts  a 
pressure  upon  the  gears,  at  the  same  instant 
do  the  spring  supports  allow  the  motor  to  rise 
or  fall  so  as  to  give  somewhat,  and  no  matter 
how  sudden  the  strain  is  brought  upon  the 
gears  it  is  always  a  progressive  one.  The  result 
in  practice  has  been  that  with  a  weight  equiva- 
lent to  two  tons  upon  each  thirty-inch  wheel 
these  wheels  have  actually  been  skidded  in 
continuous  rotation  upon  a  dry  track  and  the 
strain  necessary  to  do  this  amounts  to  from 


We  now  come  to  the  electrical  features  of  the 
motor.  The  armatures  shown  in  the  illustra- 
tions have  a  special  modified  form  of  Siemens 
winding.  The  shafts  are  built  up  of  the  finest 
forged  steel,  and  the  body  of  the  armature  is 
built  up  with  alternating  layers  of  tissue  paper 
and  very  thin  iron  discs,  such  as  are  used  in 
the  Edison  machine,  which  reduces  the  heat 
loss  due  to  Foucault  currents  to  a  minimum. 
The  difficulties  first  experienced  in  dealing  with 
currents  of  such  high  electromotive  force  and 
large  volume  have  now  been  overcome.  The 
bodies  of  the  armatures  are  thoroughly  jap- 
anned and  baked,  and  the  utmost  precaution  is 
taken  in  putting  on  the  different  coils  of  wire 


176 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


to  insulate  them  both  from  the  body  of  the 
armature  and  from  each  other  by  the  use  of  a 
material  which  offers  very  high  resistance  to 
inductive  discharges.  The  commutators  are 
built  of  the  finest  copper,  and  no  insulating 
material  is  used  other  than  that  just  mentioned 
and  fine  selected  mica. 

One  of  the  fundamental  features  of  this  sys- 
tem of  electrical  propulsion  is  to  get  rid  of  all 
adjustments  and  to  reduce  it  to  the  simplest 
possible  system  of  working  and  at  the  same 
time  to  maintain  as  high  an  efficiency  as  possi- 
ble of  the  motors  themselves.  For  this  purpose 
it  was  necessary,  because  of  the  limited  space 
available,  to  make  the  motors  of  light  weight 
and  yet  capable  of  developing  a  very  intense 


narily  extends  over  the  first  third  or  half  of  its 
speed. 

3.  Variation  in  the  speed  of  the  armature 
after  full  potential  has  been  reached  at  its 
terminals. 

The  first  characteristic  is  obtained  by  bringing 
the  field  magnets  to  a  very  high  degree  of  sat- 
uration. Current  is  then  admitted  to  the  arma- 
ture under  perfect  control,  and  the  potential  at 
the  armature  terminals  gradually  increased, 
thus  increasing  the  current  until  the  rotary 
effort  is  sufficient  to  start  the  train  from  a  state 
of  rest.  When  the  motor  is  in  this  condition 
the  torque,  or  rotary  effort,  is  directly  propor- 
tioned to  the  strength  of  the  field  magnet  and 
to  the  current  flowing  through  the  armature. 


FIG.  174. — ELEVATION  OF  SPRAGUE  CAR  TRUCK. 


magnetic  field.  The  form  adopted  for  these 
motors  has  given  these  qualities.  The  motors 
themselves  are  built  entirely  of  the  finest  se- 
lected scrap  iron  specially  forged.  It  was  neces- 
sary further  to  have  a  wide  range  of  speed  un- 
der full  potential  at  the  armature  terminals, 
and  hence  it  was  necessary,  also,  to  have  a  wide 
range  in  the  magnetic  intensity  of  the  field 
magnets. 

A  motor  when  acting  in  this  manner  is  to  be 
considered  under  three  entirely  different  con- 
ditions: 

1.  When  it  is   at   rest,  and  it  is  desired  to 
get  the  greatest  possible  torque  or  tractive  ef- 
fort.    This  tractive  effort  should  be  under  per- 
fect control  and  should  necessarily  be  greater 
than  that  which  the  motor  could  exert  for  any 
very  long  continued  time. 

2.  When  exerting  a  continuous  traction  un- 
der accelerating  speed.     This  is  necessary  in 
getting  a  train  under  way,  and  this  effort  ordi- 


As  soon,  however,  as  the  armature  starts  to  ro- 
tate, a  different  condition  exists.  It  is  now 
necessary  to  exert  a  continuous  traction;  but 
the  motor,  on  account  of  its  accelerating  speed, 
is  generating  an  increasing  electromotive  force 
of  its  own  which  is  counter  to  that  of  the 
line,  and  the  difference  between  this  counter 
electromotive  force  and  the  line  electromotive 
force  determines  the  current  through  the  arma- 
ture. Consequently,  it  is  necessary,  while 
maintaining  the  field  magnet  at  the  same 
strength,  to  still  further  raise  the  potential  at 
the  terminals  of  the  armature  by  means  of 
which  the  current  is  kept  at  the  same  strength. 
It  is  impossible  to  maintain  a  constant  tractive 
effort  in  any  other  way  under  these  conditions. 
The  potential  will  soon  equal  the  initial,  and 
the  motor  will  be  doing  its  maximum  work 
per  unit  of  time.  It  is  now  necessary  to  ac- 
celerate the  speed  of  the  train,  and  this  is 
done  by  weakening  the  field  magnets.  This 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


177 


principle  of  weakening  the  field  magnets  to  in- 
crease the  mechanical  effect  of  a  motor  at  all 
times  when  not  working  up  to  the  maximum 
was  brought  out  by  Mr.  Sprague  some  time  ago, 
when  he  enunciated  the  principle,  already  re- 
ferred to  above. 

In  a  motor  with  the  armature  and  field  mag- 
net independently  supplied,  the  work  which  the 
motor  will  do  in  a  given  time,  its  economy,  and 


strengthening  them.  The  result  is  that,  if  run- 
ning on  a  level  at  a  certain  speed  and  a  grade  is 
met,  and  it  is  desired  to  get  up  that  grade  at 
the  same  speed,  it  is  necessary  to  weaken  the 
field  magnets.  If  the  potential  falls  off  and 
it  is  desired  to  keep  up  the  same  speed,  it  is 
necessary  to  weaken  the  field  magnets,  and, 
conversely,  if  it  is  desired  to  slow  down,  it  is 
necessary  to  strengthen  the  field  magnets. 


H- 


FIG.  174a. — PLAN  OF  SPKAGUE  CAK  TRUCK. 


efficiency  are  all  independent  of  the  strength  of 
the  field  magnet,  provided  the  translating  de- 
vices intermediate  between  the  motor  and  what- 
ever is  the  recipient  of  its  energy  are  not  lim- 
ited as  to  the  rate  of  transmission  of  the  motor 
speed;  and  that  in  all  cases  where  a  motor  is 
working  on  a  constant  potential  circuit  and  not 
up  to  its  maximum  capacity,  in  order  to  in- 
crease the  mechanical  effect  either  of  speed  or 
power,  or  both,  or  to  compensate  for  any  fall- 
ing off  of  the  potential  on  a  line,  it  is  neces- 
sary to  weaken  the  field  magnets,  instead  of 


A  motor,  when  running,  may  be  considered 
as  a  dynamo  driven  by  a  current.  It  generates 
an  electromotive  force  dependent  upon  its  re- 
sultant strength  of  field  and  the  speed  of  the 
armature,  and  is  independent  of  all  other  things. 
It  follows  that  if  the  field  magnet  be  under 
proper  control,  this  counter-electromotive  force 
is  under  perfect  control  under  different  speeds, 
and  can  be  made  greater  or  less  in  relation  to 
the  initial-electromotive  force,  and  consequently 
the  motor  can  be  made  to  do  whatever  work  is 
desired  of  it. 


178 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


This  system  of  handling  a  motor,  which  is  an 
essential  departure  from  previous  methods,  has 
been  carried  out  to  its  logical  conclusion  in 
braking  the  train,  as  will  be  indicated  later. 

The  winding  of  the  field  magnets  of  the  mo- 
tors is  peculiar.  One  of  the  great  difficulties 
which  has  invariably  been  met  with  in  working 
with  motors  is  the  change  of  lead  necessary  to 
get  the  brushes  at  the  point  of  non-sparking. 
It  is  considered  necessary  when  dealing  with 
large  powers,  if  there  is  going  to  be  continuous 
and  successful  running,  to  maintain  the  brushes 
at  such  a  point.  This  change  of  the  lead, 
caused  by  a  distortion  which  is  set  up  by  the 
armature,  varies  with  every  change  of  load, 
with  every  change  of  the  armature  current, 
and  with  every  change  in  the  field-magnet 
strength.  It  has  furthermore  been  the  habit 
where  any  considerable  power  has  been  de- 
veloped to  use  two  sets  of  brushes,  one  for  for- 
ward and  the  other  for  backward  motion.  Mr. 
Sprague  has  entirely  obviated  the  necessity  for 
doing  this  by  an  arrangement  which  is  as  sim- 
ple as  it  is  efficient.  This  consists  in  the  method 
of  constructing,  winding,  and  connecting  up 
the  field  magnets.  The  latter  are  wound  with 
two  sets  of  coils.  One  of  these  is  a  fine  shunt 
coil  which  is  in  series  with  an  independent  reg- 
ulating resistance  and  produces  the  normal 
poles;  the  other  is  a  coarse  coil  in  series  with 
the  armature,  which  tends  to  produce  poles  at 
right  angles  to  the  normal  poles,  and  this  cir- 
cuit is  included  in  the  reversing  switch,  so  that 
when  the  armature  circuit  is  reversed  the  cur- 
rent in  the  coarse  coil  is  also  reversed.  There 
are  then  four  poles  set  up  in  this  machine,  two 
being  normal  and  variable  at  will,  the  other 
two  being  abnormal,  variable  poles  dependent 
upon  the  current  flowing  through  the  armature. 

In  the  normal  arrangement  of  circuits,  the 
two  sets  of  field  coils,  fine  and  coarse,  combine 
to  set  up  a  resultant  polar  line  which  is  distorted 
or  rotated  in  the  plane  of  rotation  of  the  arma- 
ture. Since  any  increase  in  the  armature  cur- 
rent causes  the  same  increase  in  the  series  field 
coils,  the  tendency  to  distortion  by  these  two 
elements  will  always  vary  to  the  same  extent, 
and  the  resultant  position  will  be  always  the 
same  no  matter  what  is  the  extent  of  variation 
of  current.  If  the  strength  of  the  field  magnet 
is  varied  independently  of  the  armature,  by 
changing  the  resistance  in  the  shunt  field  cir- 
cuit or  by  a  variation  of  potential  on  the  line, 


while  there  is  a  tendency  to  change  the  arma- 
ture distortion,  there  is  an  equal  and  opposite 
tendency  to  change  the  distortion  due  to  the 
series  field  coils,  and  so  this,  also,  has  no  effect. 
If  the  direction  of  the  armature  current  is 
changed,  so  also  is  that  of  the  current  in  the 
series  field,  and  hence  the  direction  of  each 
distortion  is  changed;  but  they  still  oppose  each 
other  and  vary  equally  and  oppositely  as  before, 
and  there  is  still  no  change  in  the  non-sparking 
points.  It  is  immaterial  whether  the  change  in 
direction  of  armature  current  is  due  to  a  change 
of  terminals  in  changing  the  direction  of  rota- 
tion of  the  motor,  or  is  caused  in  changing  the 
motor  into  a  generator  by  strengthening  the 
field.  Hence,  the  motor  will  run  in  either  di- 
rection on  a  circuit  of  constant  or  varying  po- 
tential, with  a  single  or  double  set  of  tangen- 
tial or  end-contact  brushes,  with  no  change  of 
lead,  and,  consequently,  with  no  necessity  for 
changing  the  position  of  the  brushes.  The  po- 
sition of  the  brushes  having  been  once  properly 
adjusted,  it  is  made  independent  of  the  amount 
of  work  the  machine  is  doing,  or  the  speed  at 
which  it  runs,  or  whether  it  is  acting  as  a  dyn- 
amo or  as  a  motor.  It  is  likewise  independent 
of  the  strength  of  field  and  of  the  armature 
current  so  long  as  the  magnetic  moment  of  the 
field  sufficiently  exceeds  that  of  the  armature. 
As  will  be  seen  from  the  end  view,  Fig.  172, 
there  are  at  each  end  of  the  car  three  vertical 
switch  rods,  each  connected  by  movable  links 
with  rods  running  through  from  one  end  of  the 
car  to  the  other.  These  rods  have  projecting 
fingers  which  operate  the  levers  of  three  very 
rapidly-moving  switches;  the  movement  of 
these  switches  is  independent  of  the  rapidity 
of  movement  of  the  hand,  which  simply  stores 
up  energy  until  a  certain  point  is  reached,  when 
the  lever  is  freed  and  the  switch  thrown  over 
automatically.  These  three  switches  are  em- 
ployed as  follows:  One  for  breaking  the  main 
circuit;  another  for  reversing  the  armature  cir- 
cuit; and  a  third  for  detaching  the  armature 
partially  from  the  line  and  closing  it  upon  a 
local  regulating  apparatus.  The  movement  of 
the  handles  on  the  vertical  rods  are  similar  at 
each  end.  Forward  motion  of  one  means  for- 
ward movement  of  the  car;  forward  movement 
of  another  means  closing  the  main  circuit;  and 
a  forward  movement  of  the  third  means  also  a 
throwing  off  of  the  brake  circuit.  So  that 
when  a  man  stands  at  either  end  of  the  car, 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


179 


precisely  the  same  movements  mean  the  same 
thing  as  he  looks  up  the  track.  In  addition  to 
these  three  vertical  rods,  there  is  a  fourth  rod 
which  connects  by  a  bevelled  gear  with  a  rod 
running  through  underneath  the  car,  and  pro- 
vided with  universal  joints  so  as  to  allow  of 
any  necessary  adjustment.  The  top  of  this  rod 
carries  a  wheel  very  much  like  a  brake  wheel, 
and  it  connects  with  a  regulator  which  consists 
of  a  series  of  resistance  coils.  These  are  so  ar- 
ranged that  by  the  continuous  movement  of  the 
regulator  handle  they  are  first  cut  out  of  the 
armature  circuit,  while  the  field  is  maintained 
at  a  high  saturation,  thereby  raising  the  arma- 
ture potential,  and  then  cut  into  the  field  cir- 
cuit in  reverse  manner,  thereby  weakening  the 
field.  This  regulator  governs  also  both  steps 
of  braking  the  train. 

The  current  is  taken  from  the  centre  rail  by 
three  conductors,  two  of  which  are  bronze 
wheels  working  on  pivoted  arms  under  com- 
pression springs.  They  are  provided  with  ad- 
justable nuts  to  regulate  the  tension,  and  lock 
nuts  to  prevent  the  wheels  dropping  more  than 
a  certain  limited  amount  when  leaving  the  mid- 
dle rail.  The  arrangement  of  contacts  is  such 
that  the  car  will  span  thirty -foot  spaces  without 
breaking  the  circuit.  The  other  part  of  the 
circuit  comes  through  the  wheels  of  the  truck, 
so  that  one  part  of  the  apparatus  is  continually 
grounded.  The  collector  and  the  main  circuits 
both  run  to  fusible  cut-outs  before  they  reach  the 
main  braking  circuit,  and  the  armatures  are  also 
independently  supplied  at  both  ends  with  sim- 
ilar cut-outs.  The  armatures  and  the  field  mag- 
nets are  all  in  parallel  circuit  with  each  other. 

This  is  the  first  instance  in  which  two  inde- 
pendent motors  have  been  simultaneously  con- 
trolled from  the  same  regulating  source,  and  by' 
the  methods  employed  it  is  perfectly  possible 
to  control  twenty  motors  in  the  same  way. 
When  it  is  considered  that  the  speeds  vary 
from  zero  to  1,200  revolutions  a  minute,  and  the 
speeds  of  the  two  motors  should  be  the  same, 
it  will  be  seen  how  important  a  step  has  been 
taken.  The  torque  or  rotary  effort  of  these  mo- 
tors under  slow  speeds  is  very  great,  and  they 
are  able  to  start  from  rest  and  propel  two  full- 
sized  cars  up  the  maximum  grade  on  the  ele- 
vated railroad.  The  motors  weigh  about  1,200 
pounds  each. 

We  come  now  to  the  system  of  braking,  which 
is  the  logical  sequence  of  the  system  of  control- 


ling motors  originated  by  Mr.  Sprague.  As  is 
well  known,  when  a  motor  is  in  operation  it  is 
generating  an  electromotive  force.  In  other 
words,  it  is  acting  like  a  dynamo,  and  since  this 
depends  upon  the  strength  of  the  field  magnet 
and  the  speed,  and  since  the  field  magnet 
strength  is  under  positive  control,  it  follows 
that  this  motor  electromotive  force  can  be  made 
to  equal  the  initial  motive  force  and  even  to 
exceed  it.  When  this  electromotive  force  of 
the  motor  thus  predominates,  the  machine  will 
become  a  generator  and  give  current  to  the 
line,  and  its  mechanical  effects  are  reversed  so 
that  it  brakes  the  train  instead  of  propelling 
it;  and  the  current  generated  by  it,  and  the 
braking  power,  or  reversed  mechanical  effect, 
are  now  controllable  by  further  increasing  or 
re-diminishing  the  strength  of  the  field,  and 
the  new  dynamo  can  now  be  changed  back 
into  a  motor  instantly  at  will.  The  mechan- 
ical energy  received  by  the  reversed  motor  and 
delivered  as  electricity  to  the  line  depends  upon 
the  mass  of  the  train  and  its  velocity.  In 
running  on  a  down  grade  there  would  naturally 
be  an  acceleration  of  speed,  but  this  method  of 
braking  can  limit  that  acceleration  at  any  de- 
sired point,  or  the  motor  can  be  slowed  down 
when  running  on  the  down  grade.  This  is 
done,  of  course,  by  strengthening  the  field 
magnets.  Since  the  energy  of  the  train  is  now 
being  used  to  run  the  motors  as  braking  dyn- 
amos, the  train  will  be  run  at  a  certain  constant 
speed  down  grade;  or  if  the  field  magnets  be 
still  further  strengthened,  the  train  will  slow 
down;  this  occurs  also  in  the  ordinary  process 
of  stopping.  The  diminution  of  speed,  how- 
ever, reduces  again  this  motor  electromotive 
force,  and  hence  the  field  magnet  has  to  be 
strengthened  still  further  as  a  train  slows,  until 
the  speed  is  reached  which,  with  the  strongest 
field  magnet,  will  give  a  motor  electromotive 
force  equal  to  that  of  the  line.  This  point  with 
the  motors  in  question  is  at  about  one-third 
speed,  or  seven  miles  an  hour.  Hence  eight- 
ninths  of  the  energy  of  a  train  moving  twenty- 
one  miles  an  hour  is  sent  back  to  the  line  in 
current  to  relieve  the  generating  station.  In 
fact,  the  system  as  here  set  out  has  the  advan- 
tages of  a  cable  road,  together  with  other  ad- 
vantages which  the  cable  road  does  not  pos- 
sess; because  not  only  do  the  trains  running  on 
down  grades  help  the  trains  running  on  up 
grades,  but  those  which  are  slowing  down  like- 


180 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


wise  give  up  their  energy  to  the  system.  In 
fact,  this  system  is  one  in  which  trains  slowing 
down  and  running  on  down  grades  supply  the 
current  for  trains  running  on  up  grades  and 
starting,  and  the  central  station  becomes  a  dif- 
ferential factor  to  make  up  for  the  loss  of  con- 
version and  reconversion  and  to  provide  for 
traction  and  loss  in  the  conductors. 

Were  the  machines  perfect  converters  of  en- 
ergy, this  would  make  the  power  taken  by  a 
system  almost  independent  of  grades  and  stops, 
and  would  simply  be  that  necessary  to  provide 
for  continuous  traction  and  for  loss  on  conduct- 
ors. Of  course,  this  perfection  of  conversion 
can  never  be  reached.  It  does,  however,  make 
a  difference  of  forty  per  cent,  in  the  power  re- 
quired to  operate  the  electric  railroads  at  the 
central  stations,  in  the  losses  on  conductors  of 
a  given  size,  and  in  the  investment  necessary 
in  the  central  stations.  As  a  matter  of  fact, 
there  would  be  required  at  the  central  station 
only  such  horse  power  as  is  to-day  actually  de- 
veloped at  any  one  moment  on  the  elevated 
railroads,  which  is  only  about  two-fifths  of  the 
capacity  of  the  motors  or  engines. 

Hence,  instead  of  7,215  amperes  of  current 
being  supplied  from  the  central  stations  at  two 
points,  it  is  supplied  from  as  many  additional 
moving  stations  as  there  are  trains  being 
checked  on  a  down  grade  and  stopping.  Sixty 
per  cent,  only  of  this  current  would  come  from 
the  main  station;  that  is,  4,329  amperes,  or  2,165 
from  each. 

The  final  step  of  braking  is  done  by  partially 
detaching  the  armature  from  the  main  line 
when  its  motor  electromotive  force  is  equal  to 
that  of  the  initial,  at  which  moment  there  is  no 
current  flowing  through  it,  and  closing  it  upon 
the  same  local  regulating  apparatus  which  is 
used  for  regulating  the  speed  and  power,  and 
the  first  step  of  braking.  By  this  means  the 
train  can  be  brought  to  a  full  stop.  All  these 
steps  of  braking  are  under  the  most  perfect 
control,  but  if  necessary  the  braking  can  be  so 
sudden  as  to  cause  the  wheels  to  have  a  contin- 
uous skidding  rotation;  not  such  a  skidding  as 
is  caused  when  an  air  brake  is  put  on  too  hard, 
but  a  rotating  slip  which  will  be  just  enough  to 
relieve  the  armature  when  the  strain  on  it  has 
come  to  a  certain  point.  This  is  the  most  per- 
fect method  possible  of  braking,  because  fixed 
skidding  is  an  impossibility,  and  the  wheels  will 
turn  until  the  train  comes  to  a  dead  stop,  al- 


though where  the  braking  power  is  put  on  too 
suddenly  and  exceeds  the  grip  of  the  wheels, 
they  will  relieve  themselves  by  slipping  just 
enough  to  keep  the  braking  at  the  maximum 
limit. 

With  the  switch  in  position  for  the  last  step 
of  braking,  the  car  can  be  allowed  to  creep 
down  the  maximum  grades  at  a  snail's  pace 
with  a  movement  so  slow  as  to  be  almost  im- 
perceptible. 

It  is  the  customary  practice  to  stop  at  the 
Second  avenue  station  of  the  elevated  railroad, 
which  is  on  a  ninety-five  foot  grade,  without 
the  use  of  any  shoe-brakes,  although  the  rear 
truck  is  fitted  with  these  and  can  be  operated 
at  either  end  of  the  car. 

By  a  slight  reversal  of  the  armature  effort, 
the  car  will  stand  at  a  dead  rest  on  this  grade. 

The  energy  of  the  train  which  is  expended  in 
the  last  step  of  braking  can  be  used  in  heating 
the  car,  and  some  interesting  experiments  are 
now  being  carried  on  at  the  Thirty-fourth  street 
station. 

It  should  be  noted  that  at  present  the  generat- 
ing station  for  this  experiment  is  situated  on 
Twenty-fourth  street,  so  that  the  current  at 
times  is  carried  about  three-fourths  of  a  mile. 
The  proper  electromotive  force  is  obtained  by 
coupling  together  five  Edison  machines  in 
series.  The  wire  used  is  No.  1  B.  W.  G.,  and  is 
carried  on  the  Western  Union  Telegraph  poles. 
Mr.  Sprague  has  by  no  means  rested  satisfied 
in  developing  his  system  of  railway  and  carry- 
ing it  to  the  advanced  condition  in  which  it  now 
is,  but  he  has  been  engaged  in  equipping  the  sta- 
tion and  cars  along  the  line  of  the  road  with 
Edison  lamps,  which  are  run  in  series  from  the 
same  high  constant  potential  circuit  that  sup- 
"plies  the  car,  on  a  system  which  has  been  de- 
veloped by  Mr.  E.  H.  Johnson,  the  president  of 
the  company. 

A  resume  of  the  special  and  distinctive  feat- 
ures of  Mr.  Sprague's  system  may  not  be  unin- 
teresting, and  is  therefore  given  below: 

A  double-track  system  with  motors  working 
in  parallel  circuit  with  each  other  on  a  constant 
potential  circuit,  the  two  tracks  being  supplied 
from  the  same  source  and  from  the  same  main 
conductors. 

A  supply  at  two  or  more  points  by  inde- 
pendent batteries  of  automatically  non-spark- 
ing machines,  the  points  of  supply  being 
maintained  at  the  same  differences  of  potential. 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


181 


A  system  of  continuous  main  conductors  in- 
tersected by  switches,  and  sectional  working 
conductors  connected  therewith  through  auto- 
matic safety  devices. 

Means  for  cutting  out,  either  automatically, 
in  case  of  accident,  or  at  will,  if  desired,  any 
portion  of  the  circuit. 

An  automatic  block  signal  system  for  day 
and  night  use. 

Methods  for  the  equalization  of  potential  by 
cross  connections  between  conductors  of  like 
polarity  and  on  different  tracks. 

A  very  simple  construction  of  the  motor 
proper. 

The  centreing  of  the  motor  upon  the  axles  so 
as  to  maintain  parallelism  between  the  driving 
shaft  and  the  driven  axle. 

The  method  of  flexibly  supporting  a  part  of 
the  weight  of  the  motor  from  the  truck  so  as 
to  allow  perfect  freedom  in  following  the  mo- 
tions of  the  independent  axle's. 

The  method  of  doing  away  with  all  shock 
and  jar  and  danger  of  stripping  the  gears,  and 
the  maintaining  at  all  times  of  a  spring  touch 
so  as  to  prevent  any  backlash  and  to  insure 
quiet  running. 

Double  driving  from  opposite  ends  of  the  mo- 
tor shaft. 

The  use  of  fixed  and  adjustable  split  gears. 

The  means  for  getting  a  very  intense  rotary 
effort  in  starting  by  having  an  intense  mag- 
netic field  and  raising  the  armature  potential 
gradually. 

The  means  for  maintaining  a  continuous  and 
equal  traction  until  full  potential  has  been 
reached. 

The  method  of  increasing  or  decreasing  the 
mechanical  effects,  whether  of  speed  or  power, 
or  both,  by  an  inverse  varying  of  the  field-mag- 
net strength. 

The  method  of  controlling  two  or  more  inde- 
pendent motors  simultaneously  from  the  same 
source  and  by  the  same  apparatus. 

The  use  of  a  single  resistance  for  both  the 
armature  and  field  circuits,  each  working  in- 
dependently. 

The  method  of  winding  to  maintain  the  point 
of  least  sparking  at  a  fixed  position,  inde- 
pendent of  the  load,  speed,  or  power. 

The  use  of  single  sets  of  brushes  for  both 
forward  and  backward  motion. 

A  system  of  braking  consisting  in  converting 
the  energy  of  the  train  into  current,  which  is 


delivered  back  to  the  line  through  the  same  ap- 
paratus which  propels  the  car  without  any  re- 
versal of  contacts,  whereby  a  saving  of  at  least 
forty  per  cent,  would  be  effected  in  the  size  and 
capacity  of  the  generating  station,  in  the  con- 
ductors, and  in  the  coal  and  labor  expended 
at  generating  stations. 

The  final  step  of  braking  by  means  of  which 
the  car  is  brought  to  rest  through  the  same 
dynamic  action  of  the  motor  while  the  field 
magnets  are  still  connected  with  the  line. 


23 


FIG.  175. — HKNRY  ELECTRIC  MOTOK  FOR  RAILWAYS. 

The  method  of  lighting  cars  and  stations  from 
the  main  station. 

The  method  of  heating  cars  with  a  part  of 
the  energy  of  the  momentum. 

Another  of  the  workers  in  the  field  of  electric 
railroading  is  Mr.  John  C.  Henry,  of  Kansas 
City,  who  has  been  busy  for  some  time  past  in 
elaborating  a  system  which  possesses  several 
novelties  and  is  now  going  into  use.  Without 
entering  into  the  various  methods  employed  by 
Mr.  Henry  in  distributing  and  taking  off  the 
current  from  the  conductor,  either  overhead  or 
underground,  we  will  only  describe  the  locomo- 
tive car  itself  and  its  arrangement.  This  is 
shown  in  Figs.  175  and  176,  which  represent 
respectively  a  transverse  sectional  view  and  a 
plan  of  the  car. 


182 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


The  principal  objects  aimed  at  in  its.construc- 
tion  are  to  make  each  motor  automatically 
adapt  itself  to  every  change  in  load  and  grade, 
and  to  afford  safety  devices  by  which  no  inju- 
rious effect  could  be  produced  through  abnormal 
conditions  of  working.  Mr.  Henry  has  also 
adopted  an  arrangement  by  which  the  motor  is 
kept  at  a  constant  uniform  speed,  irrespective 
of  the  speed  of  the  car. 

As  will  be  seen  by  the  illustrations,  the  motor 
is  mounted  on  a  frame  D,  which  permits  a  di- 
rect connection  to  be  made  with  the  axle  from 
the  driving  shaft  of  ths  motor  E.  For  the  pur- 


For  the  purpose  of  automatically  reversing 
the  poles  of  the  motor,  the  two  opposite  poles 
of  the  switch  T  are  connected  to  wires  running 


FIG.  176. — HENRY  ELECTRIC  MOTOR  FOR  RAILWAYS. 

pose  of  automatically  controlling  the  supply  of 
the  current  to  the  motors,  the  driving  shaft  G 
of  the  motor  is  connected  by  the  bevel  gear  i 
with  the  upright  shaft  k,  carrying  the  governor 
K.  A  sleeve  P,  on  the  shaft  k,  is  attached  to 
the  governor  at  one  end,  and  from  the  sleeve 
there  extends  an  arm  m,  carrying  the  rack  M, 
which  gears  with  the  pinion  N.  Encircling  the 
latter  is  a  series  of  resistance  coils  0  in  electrical 
connection  with  the  main  conductors  through 
brush  n1  and  lever  n  and  branch  conductors. 
When  from  any  cause  the  speed  of  the  motor 
shaft  varies  from  the  prescribed  limit,  the  rack 
N  is  drawn  up  or  down  by  the  governor  K, 
which  moves  the  contact  brush  n1  over  the  com- 
mutator of  the  resistance  coils,  increasing  or 
decreasing  the  resistance  to  the  current. 


FIG.  177. — SIDE  VIEW,  HIGHAM  MOTOR. 

to  the  motor  field  and  to  the  commutator  brush 
A  segment  rack    lever  s2  gears  with  the 


9. 


pinion  of  the  switch,  and  a  spring  s3,  attached 


FIG.  178. — SECTION,  HIGHAM  MOTOR. 


to  the  lever,  keeps  the  rack  in  one  position  un- 
der tension.  The  opposite  end  of  the  lever  s2 
is  prpvided  with  the  armature  s1,  and  in  the 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


183 


field  of  the  electro-magnets  s.  Two  short  cir- 
cuits extend  from  branch  conductors  in  elec- 
trical connection  with  the  magnets  s.  A  circuit 
closer  s6  is  also  provided,  the  key  of  which  is 
held  in  a  horizontal  position  by  means  of  a 
spring  s5.  The  electro-magnet  s  is  also  con- 
nected to  the  circuit  closer.  With  this  arrange- 
ment, should  the  shaft  of  the  motor  attain  a 
rate  of  speed  above  that  necessary  to  propel 
the  car,  the  governor  is  thrown  out,  thereby 
drawing  down  the  sleeve  P,  and  the  projection 
P1  depresses  the  key  of  the  circuit  closer  s6,  the 


terlocking  device  is  held  by  pins  q".  The  lever 
g  extends  from  the  shaft  G  to  the  lower  part  of 
the  supporting  base  to  the  speed  gearing,  to 
which  it  is  pivoted.  One  part  of  the  lever  is 
extended  at  right  angles  as  a  foot  lever,  and  a 
short  portion  g2  extends  downward  and  is  ta- 
pered at  right  angles,  so  as  to  engage  with  the 
gear-sector  g*,  which  is  pivoted  to  the  frame  D. 
A  hand  lever  extends  vertically  from  the  gear- 
sector  g*,  to  which  it  is  attached,  and  a  lever  ga 
is  attached  to  the  same  point,  and  also  in  rigid 
connection  with  the  hand  lever,  and  is  connected 


FIG.  179. — PERSPECTIVE,  VAN  DEPOELE  STREET  CAR  MOTOR. 


magnets  s  become  excited  and  draw  down  ar- 
mature s1  on  lever  s2.  This  rotates  the  pole 
changer  T,  which  changes  the  polarity  of  the 
motor  and  allows  it  to  generate  instead  of  draw- 
ing upon  the  current.  When  the  poles  of  the 
motor  are  reversed  and  the  motor  is  acting  as 
a  generator,  the  current  is  shunted  from  the 
resistance  coils  through  a  leak  circuit,  the  cir- 
cuit being  made  through  the  circuit  closer  ss. 
The  speed  of  the  motor  is  indicated  by  means 
of  the  needle  I  on  the  indicator  L. 

The  driving  shaft  G  of  the  motor  is  provided 
with  an  intermediate  friction-clutch  H,  placed 
in  connection  between  the  motor  E  and  gear  Js. 
One  portion  of  the  clutch  H  is  provided  with  a 
neck  g1,  in  which  the  end  of  lever  g  of  the  in- 


with  the  end  of  the  reciprocating  plunger  i1, 
which  is  reciprocated  in  the  direction  of  the 
speed  gearing  and  for  engaging  the  gear.  Thus 
when  it  becomes  necessary  to  change  the  speed 
of  the  car  or  change  the  relation  of  the  gear 
without  checking  the  speed  of  the  motor- shaft, 
the  foot  lever  is  operated  to  throw  the  friction- 
clutch  H  apart.  This  releases  the  end  g1  of 
lever  g  from  the  gear-sector  g*  and  the  hand 
lever  is  then  operated  to  throw  the  plunger  in 
or  out  of  connection  with  the  various  gears. 
The  gear  Jl  on  the  shaft  meshes  with  gear  J2, 
and  the  gear  «/2  is  mounted  upon  the  same  shaft 
i*  as  the  speed  gearing,  which  in  turn  commu- 
nicates power  to  the  gear  B 2,  attached  to  the 
axle  S1. 


184 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


While  all  these  arrangements  are  by  their  nat- 
ure designed  to  be  more  or  less  automatic,  Mr. 
Henry  has  also  introduced  devices  for  reducing 
the  rate  of  speed  when  required  by  means  of 
the  ribbon  brake  F.  It  is  further  evident  that 
the  contact  brush  of  the  resistance  coils  may 
also  be  moved  by  hand  for  starting,  checking, 
or  reversing  the  motor. 

In  the  early  part  of  this  work,  mention  was 
made  of  the  Elias  motor  in  which  two  electro- 
magnetic rings,  one  within  the  other,  acted  as 
a  motor  by  mutual  attraction  and  repulsion. 
The  same  relative  arrangement  of  armature 


FIG.  180. — VAN  DEPOELE  MOTOK. 

and  field  has  been  adopted  by  Messrs.  E.  T. 
Higham  and  Daniel  Higham,  of  Philadelphia. 
They  have,  however,  introduced  modifications 
which  are  designed  to  improve  the  efficiency  of 
the  arrangement. 

The  motor  is  shown  in  side  view  and  in  sec- 
tion in  Figs.  177  and  178,  and  will  be  seen  to 
consist  of  two  ring  magnets  of  the  Gramme 
type.  The  inner  magnet  revolves  while  the 
outer  remains  stationary,  but  both  are  provided 
with  commutators.  The  current  coming  in, 
say  at  the  brush  H,  passes  through  the  contact 
wheel  F  to  the  commutator-plates  with  which 
they  happen  to  be  in  contact,  and  thence 
through  the  corresponding  conductors  to  the 


coils  of  both  the  electro-magnetic  rings,  there 
splitting  and  passing  in  opposite  directions 
through  opposite  halves  of  each  ring  of  coils 
and  out  through  the  contact  wheel  F'  and  brush 
H'.  Thus  the  travelling  contacts  rotate  the 
polar  points  of  both  electro-magnetic  rings  in 
the  same  direction  as  that  in  which  the  rotary 
electro-magnet  moves  mechanically  and,  as  a 
result,  it  is  said,  the  power  developed  by  the 
motor  is  increased. 

We  have  already  in  Chapter  VII.  drawn  at- 
tention to  and  described  the  electric  rail- 
way work  accomplished  by  Mr.  Van  Depoele 
in  his  equipment  of  the  lines  at  Appleton, 
Wis.,  Montgomery,  Ala.,  and  in  other  places, 
but  without  special  reference  to  the  type 
of  motor  employed  for  that  purpose.  Hence 
a  description  of  the  latter  will  now  be  of  in- 
terest. 

The  motor  which  is  illustrated  in  the  accom- 
panying engraving,  Fig.  170,  has  an  armature 
of  the  well-known  Gramme  ring  form,  and  the 
shaft  rests  in  bearings,  one  of  which  is  a 
bracket  bolted  to  the  lower  pole  piece,  while 
the  other  is  the  neutral  point  of  the  field  mag- 
nets. Having  special  regard  to  the  attainment 
of  compactness,  the  field  magnets  are  given 
the  form  shown.  It  will  be  seen  that  the  field 
coils  are  wound  on  the  two  sides  of  a  cast-iron 
upright  upon  the  ends  of  which  are  bolted  the 
pole  pieces  which  project  at  right  angles  and 
encircle  the  armature. 

As  the  direction  of  travel  of  the  car  must  be 
under  control,  two  pairs  of  brushes  are  provided 
by  which  the  direction  of  rotation  of  the  motor 
can  be  changed  at  will.  Each  pair  of  brushes 
is  attached  to  a  brush-holder  provided  with  a 
lever,  by  the  shifting  of  which  either  pair  can 
be  brought  in  contact  with  the  commutator. 
The  end  of  the  armature  shaft  carries  a  gear 
wheel,  which  meshes  into  another  attached  to 
the  car  axles. 

In  order  to  provide  for  the  regulation  of  the 
motor  so  that  it  may  run  at  different  speeds, 
and  without  the  use  of  external  resistances, 
Mr.  Van  Depoele  adds  to  the  ordinary  field- 
magnet  coils  additional  ones,  which  are  suc- 
cessively connected  to  each  other  in  series  and 
are  also  in  series  with  the  main  field  coils. 
This  is  shown  diagrammatically  in  Fig.  180, 
which  represents  the  method  adopted  for  the 
automatic  regulation  of  the  motor.  It  will  be 
seen  that  the  coils  a1,  a2,  etc.,  are  brought  out 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


185 


to  spring  terminals  over  which 
is  placed  a  contact  bar  /.  One 
end  of  this  bar  carries  an  ad- 
justable weight  J,  which  tends 
to  press  down  on  the  terminal, 
1,  2,  3,  etc.  The  other  end  of 
the  contact  bar  is  provided 
with  an  iron  armature  K,  in 
close  proximity  to  the  surface 
of  the  pole  piece  C,  so  that 
when  attracted  by  the  mag- 
netic condition  of  the  latter 
the  other  end  is  drawn  away 
from  the  contact  springs,  thus 
cutting  out  the  resistances. 

This  arrangement,  shown  in 
Fig.  180,  is  evidently  intended 
for  motors  in  which  it  is  desired 
to  keep  the  current  and  speed 
constant.  But  in  the  motor 
shown  in  Fig.  17!),  which  is  ap- 
plied to  the  street  cars  where 
these  conditions  do  not  pre- 
vail, a  system  of  hand  regula- 
tion has  been  adopted.  The 
auxiliary  field  coils  are  con- 
nected to  a  commutator  which 
is  manipulated  by  hand,  and 
by  means  of  which  any  speed 
from  rest  to  maximum  can  be 
obtained. 

We  have  in  Chapter  VI. 
made  mention  of  the  early 
work  of  Mr.  Stephen  D.  Field, 
in  the  domain  of  electric  rail- 
roading. His  most  recent 
work  now  deserves  mention 
here  as  it  is  marked  with  the 
usual  originality  of  the  in- 
ventor, and  is  on  the  eve  of 
practical  demonstration. 

Being,  like  others,  impressed 
with  the  special  applicability 
of  electric  motors  to  the  pro- 
pulsion of  the  cars  on  the  ele- 
vated railroads  in  this  city, 
and  encouraged  in  this  proj- 
ect, we  believe,  by  his  uncle, 
Mr.  Cyrus  W.  Field,  Mr.  Field 
has  for  some  time  past  de- 
voted his  special  attention  to 
the  problem  involved,  and  has 
so  far  matured  his  plans  that 


186 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


actual  work  of  construc- 
tion is  now  progressing, 
looking  to  a  practical 
test. 

Taking  in  review  the 
mechanical  details  first, 
it  will  be  seen  that  be- 
tween  the  wheels  of  the 
car  truck  a  single  motor 
is  situated,  the  armature 
shaft  of  which  is  con- 
nected directly  to  the 
wheels  by  means  of  a 
crank  and  side  connect- 
ing-rod similar  to  that 
employed  on  steam  loco- 
motives. This  is  clearly 
shown  in  Figs.  181  and 
182,  which  represent,  re- 
spectively, a  side  and  an 
end  elevation  of  the 
truck  as  it  is  being  con- 
structed. The  cranks, 
as  shown,  are,  for  obvi- 
ous reasons,  keyed  to 
the  armature  shaft  at  an 
angle  of  ninety  degrees. 

The  manner  of  suspen- 
sion of  the  motor  is 
clearly  shown  in  Fig. 
181.  The  upper  and 
lower  field  magnets, 
which  form  consequent 
poles,  are  held  together 
by  the  usual  iron  con- 
necting pieces  or  yokes, 
and  through  each  of 
these  passes  an  axle  of 
the  truck,  so  that  the 
entire  weight  of  the  mo- 
tor is  equally  distributed 
on  both  axles.  The  bear- 
ing, however,  is  not  a 
rigid  one.  Although,  as 
stated  above,  the  axles 
pass  through  the  yokes 
of  the  field  magnets,  it 
will  be  observed,  Figs. 
183  and  184,  that  the  lat- 
ter are  made  up  of  two 
pieces,  or  perhaps,  to  put 
it  more  correctly,  that  a 
cap  is  bolted  to  the  real 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


187 


connecting  piece  at  each  end.  Fig.  183  shows 
the  bearing  in  end  elevation  and  part  of 
the  adjoining  wheel ;  while  Fig.  184  is  a  sec- 
tional view  which  shows  the  usual  spring  in- 
terposed between  the  weight  and  the  bearing. 
The  cap  maintains  the  spring  and  bearing  in 
position  and  allows  the  motor  free  vertical  mo- 
tion without  strain,  due  to  inequalities  in  the 
road-bed. 

The  armature  turns  in  bearings  formed  by 
the  junction  of  four  brass  arms  on  each  side  of 
the  armature,  and  these  arms  are  in  addition 
bolted  to  braces  on  each  side,  which  converge 
and  are  joined  to  the  connecting  piece  of  the 


vice  will  be  understood  from  the  illustrations, 
Figs.  181  and  183,  which  show  the  contact 
wheel  held  by  brackets  bolted  to  the  yoke  of  the 
field  magnet. 

The  wheel  itself  is  built  up  of  alternate  layers 
of  discs  6  inches  and  9  inches  in  diameter,  of  thin 
spring  brass,  so  that  each  large  disc  is  flexible, 
and  in  bearing  upon  the  rail  can  be  given  a 
bending  motion.  It  will  be  noted,  at  the  same 
time,  that  the  forked  rod  supporting  the  wheel 
passes  through  two  brackets,  above  the  upper 
one  of  which  is  a  lever  attached  to  the  rod. 
This  lever  can  be  swung  through  an  arc  of  180 
degrees  and  can  be  clamped  in  any  position ; 


a*.  worU,x.r. 


FIGS.  183  AND  184. — BEARING  OF  MOTOR  ON  CAR  AXLE. 


field  magnets  by  means  of  bolts  and  turn- 
buckles.  In  this  way  all  horizontal  motion  of 
the  motor  relatively  to  the  truck  is  prevented, 
while  at  the  same  time  its  vertical  motion  is  not 
restricted. 

The  body  of  the  car  rests  on  springs,  which 
are  bolted  to  the  tops  of  the  yokes,  the  king- 
bolt fitting  into  a  bearing  bolted  to  the  centre 
of  the  upper  pole  piece. 

There  remains  still  another  mechanical  detail 
to  be  described,  and  that  is  the  manner  in 
which  the  current  is  taken  from  the  central  in- 
sulated rail.  It  is  well  known  that  dirt  and 
rust  not  infrequently  cause  defective  contacts 
and  introduce  resistance  into  the  motor  circuit. 
To  guard  against  this,  and  in  order  to  insure 
good  contact  under  all  conditions,  Mr.  Field  has 
designed  what  may  be  called  a  combined  con- 
tact wheel  and  brush.  The  nature  of  the  de- 


the  position  of  the  contact  wheel  relative  to  the 
rail  corresponding  to  that  of  the  lever. 

Now,  it  will  be  readily  understood  that  when 
the  lever  is  in  the  middle  position  on  the  arc, 
the  wheel  stands  as  shown  in  Fig.  182,  and  only 
a  rolling  contact  is  maintained  between  wheel 
and  rail.  But  if  the  lever  should  be  turned 
slightly  to  either  side,  so  that  the  discs  are  no 
longer  parallel  to  the  rail,  a  slight  rubbing  or 
scraping  motion  would  be  added  to  that  of  the 
rolling.  By  turning  the  lever  still  more  and  in- 
creasing the  angle,  the  rubbing  component,  as 
it  were,  can  be  increased  to  any  desired  extent 
until,  when  the  lever  is  at  an  angle  of  ninety 
degrees  from  its  original  position,  the  wheel 
stands  at  right  angles  to  the  rail  and,  obviously, 
rubbing  alone  can  take  place.  The  wheel  be- 
ing built  up  in  the  manner  described  above, 
acts  as  a  resilient  brush,  taking  off  the  current 


188 


THE  ELECTRIC  MOTOR  AND   ITS  APPLICATIONS. 


and  keeping  the  rail  clean.     It  is  evident  that  matically    at    the    non-sparking  points.     The 

this  brushing  action  need  only  be  resorted  to  reader  will  have  noticed  in  Fig.  181  that  four 

when  necessary,  the  wheel  otherwise  taking  up  brushes  are  shown  bearing  on  the  commutator, 

the  current   by  the  rolling    contact,   a  spiral  but  for  the  sake  of    clearness  only  two  are 


FIG.  185. — REGULATING  MOTOR  AND  ADJUSTABLE  BRUSHES. 


spring  being  provided  which  presses  the  wheel 
upon  the  rail. 

We  come  now  to  the  electrical  details,  taking 
up  first  the  manner  in  which  the  motor  is  regu- 
lated and  the  brushes  are  maintained  auto- 


shown  in  Fig.  185,  one  each  of  the  horizontal 
and  vertical  pairs.  The  office  of  the  auxiliary 
brushes  will  appear  presently.  The  brushes 
are  all  mounted  upon  a  ring,  on  the  outer  pe- 
riphery of  which  screw  gear  teeth  are  cut,  and 


LATEST  AMERICAN   MOTORS  AND   MOTOR  SYSTEMS. 


189 


into  which  meshes  a  screw  which  forms  the 
end  of  the  armature  shaft  of  a  small  motor. 

The  horizontal  pair  are  the  main  hrushes, 
while  the  vertical  pair  are  what  may  be  called 
the  regulating  brushes.  The  field  of  the  regu- 
lating motor  is  connected  in  shunt  to  the 
armature  of  the  large  main  motor,  while  the 
armature  of  the  regulating  motor  is  connected 
to  the  regulating  brushes. 

From  what  has  just  been  said,  it  will  be  evi- 
dent that  when  the  normal  amount  of  current 
passes  through  the  motor,  the  regulating 
brushes  bear  upon  the  commutator  at  points  of 
equal  potential,  and  hence  no  current  passes 
through  the  regulating  motor.  Now  if  while 
in  this  position  any  change  of  load  or  speed 
occurs,  the  diameter  of  commutation  would  be 
changed,  and  the  regulating  brushes  not  yet 
having  changed  their  position,  would  bear  upon 
points  between  which  there  now  exists  a  differ- 
ence of  potential.  This  evidently  would  cause 
a  current  to  pass  through  the  regulating  motor, 
which  would  be  started  revolving  in  a  direction 
corresponding  to  the  change  of  conditions. 
The  turning  of  the  little  motor  gearing  with 
the  ring  causes  all  the  brushes  to  be  shifted 
simultaneously  until  the  regulating  brushes 
reach  again  points  of  equal  potential,  when 
evidently  the  little  motor  stops  for  want  of  cur- 
rent. The  main  brushes  will  at  the  same  mo- 
ment have  arrived  at  the  proper  diameter  of 
commutation.  In  this  way  the  motor  ac- 
commodates itself  automatically  to  changes  of 
load  or  speed. 

There  are  several  details  in  connection  with 
this  regulating  device  which  are  also  worthy  of 
notice.  By  referring  to  Fig.  186,  it  will  be  seen 
that  while  the  lower  main  brush  bears  against 
the  inner  end  of  the  commutator,  the  small 
regulating  brilsh  bears  at  the  outer  end.  It 
will  further  be  noted  that  only  every  fifth  com- 
mutator bar  is  continuous,  the  four  intermedi- 
ate ones  being  divided  near  the  outer  end. 
One  of  these  intermediate  bars  is  shown  in  sec- 
tion in  Fig.  180.  The  outer  end  is  entirely 
insulated,  and  hence  receives  no  current  what- 
ever from  the  motor  ;  the  insulated  pieces  thus 
serving  merely  as  a  continuous  bearing  for  the 
regulating  brushes.  From  this  it  will  be  seen 
that  while,  as  usual,  the  main  brushes  are  in 
continuous  electrical  contact  with  the  motor, 
the  regulating  brushes  only  make  contact  at 
every  fifth  commutator  bar.  In  this  way  the 

24 


regulating  motor  is  caused  to  act  under  short 
impulses  of  current.  The  effect  of  this  is  that 
while  the  regulating  motor  is  started  promptly, 
it  comes  to  rest  very  quickly  when  the  brushes 
reach  the  neutral  point  where  they  should  re- 
main, and  thus  they  are  prevented  from  travel- 


FIG.  186. — DETAILS  OF  COMMUTATOR. 

ling  beyond  that  point  by  the  momentary 
impulses  which  otherwise  would  immediately 
send  reverse  currents  into  the  motor. 

The  brush-holders  being  rigidly  attached  to 
the  ring,  some  provision  must  be  made  for 
guarding  them  against  injury,  as  they  bear 
almost  vertically  against  the  commutator.  This 
is  accomplished  in  a  manner  shown  in  Figs. 
185,  186,  and  187,  which  give  different  views  of 


190 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


the  brush-holders.  The  brushes,  as  will  be 
seen,  are  held  in  a  clamp  provided  with  pivots 
which  slide  in  slots  in  the  holder,  the  brushes 
being  pressed  toward  the  commutator  by  two 
springs.  Now,  when  the  direction  of  rotation 
of  the  armature  is  reversed,  the  brushes  are 
pushed  inwardly  a  short  distance  and  then  car- 
ried over  until  their  angle  of  bearing  is  re- 
versed, the  motion  being  limited  by  the  stop 
screws  shown  ;  then  the  springs  again  press  the 
brushes  against  the  commutator  as  before. 

In  addition  to  the  automatic  method  of  regu- 
lation above  described,  resistances  are  provided 
and  a  reversing  lever,  so  that  the  strength  of 
current  and  the  direction  of  rotation  of  the 
motor  can  be  regulated  at  will.  The  lever  is  so 
arranged  that  it  cannot  be  reversed  as  long  as 
there  is  any  current  in  the  motor. 


FIG.  187. — DETAILS  OF  BRUSH-HOLDER. 

Another  feature  is  the  electrical  brake,  which 
may  be  applied  at  will  and  to  any  degree  of 
pressure.  The  current  operating  can  be  regu- 
lated by  a  resistance  switch.  The  switch  is  so 
arranged  that  at  the  last  section,  when  the 
brake  is  to  be  taken  off,  a  reverse  current  is 
sent  into  the  brake  coils  by  means  of  an  induc- 
tion coil  or  condenser  placed  in  the  circuit ;  this 
momentary  reverse  current  instantly  demagnet- 
izes the  brakes,  so  that  they  fall  away  freely 
from  the  wheels. 

These  points  comprise  the  essential  details  of 
the  Field  motor  arrangements.  The  work  of 
construction  is  now  actively  going  on,  and 
within  a  short  while  a  practical  trial  will  be 
made  on  the  elevated  railroads  of  this  city. 

Mr.  Field  has,  however,  looked  farther  abroad 
than  the  city  in  the  application  of  electric  rail- 
ways, and  is  elaborating  plans  for  an  electric 
locomotive  designed  for  rapid  suburban  transit. 
Our  illustration,  Fig.  188,  shows  the  general 
design  of  a  locomotive  and  baggage  car  com- 


bined. It  is  proposed  to  employ  six-foot  drivers 
coupled  direct  to  the  armature  shaft.  The 
machine  is  to  be  a  four-pole  Gramme,  with  an 
armature  of  four  feet  in  diameter,  and  a  speed 
of  from  thirty  to  forty  miles  an  hour  will  be 
attainable. 

For  several  months  past  an  electric  railway 
has  been  in  operation  on  Ridge  avenue,  Phila- 
delphia, running  for  a  distance  of  about  two 
miles,  and  having  one  terminus  at  the  Laurel 
Hill  Cemetery.  This  line  was  constructed  by 
the  Union  Electric  Company,  under  the  direc- 
tion of  Mr.  W.  M.  Schlesinger,  and  has  been  in 
daily  successful  operation. 

In  order  to  avoid  overhead  conductors  and  also 
the  use  of  the  rails  as  conductors,  the  mains 
have  been  placed  in  a  conduit  having  a  slot  at 
the  top  for  a  lever  which  leads  the  current  from 
the  conductors  to  the  motor  on  the  car,  Fig. 
189.  In  designing  the  conduit,  it  was  found  in- 
advisable to  cut  through  the  cross-ties  of  the 
railroad,  as  these  form  in  most  cases  the  foun- 
dation of  the  track.  Practical  experience  has 
proved  that  a  small  conduit  having  good  sewer 
connections  answers  all  purposes.  The  main 
conduit  is  therefore  only  9  inches  deep  by  5J 
inches  wide.  It  is  built  in  sections  of  from  fifteen 
feet  to  twenty  feet,  of  heavy  channel  iron  rest- 
ing on  the  cross-ties ;  substantial  cast-iron 
wedges,  resting  also  on  the  cross-ties,  hold  the 
two  sides  of  the  conduit  at  the  proper  distance 
from  each  other  at  the  bottom  and  leave  an 
opening  £  inch  in  width  between  the  lower 
flanges.  To  the  sides  of  the  channel  iron,  at 
proper  distances,  small  angle  irons  are  riveted 
to  keep  the  slot  of  the  conduit  at  the  proper  size. 
Braces  are  attached  to  the  angle  irons  which 
pass  through  either  cross-tie  or  stringer  and  are 
provided  with  nuts  by  means  of  which  they  can 
be  tightened  or  slackened  at  will.  An  auxiliary 
conduit  is  put  down  below  the  cross-ties,  built 
either  of  wood  or  cement.  At  convenient  places 
this  connects  with  large  manholes  at  the  sides 
of  the  track,  and  these  again  communicate 
with  the  sewers.  Water  and  small  particles  of 
dirt  fall  through  the  opening  made  by  the 
wedges  between,  the  channel-iron  into  this 
lower  trough  and  pass  from  them  to  the  man- 
holes and  sewers.  But  to  prevent  any  accumu- 
lation in  the  upper  conduit,  this  opening  is  at 
proper  intervals  increased  to  five  inches  by  cut- 
ting away  a  part  of  the  lower  flanges  of  the 
channel  iron. 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


191 


The  greatest  difficulty  experienced  with  un- 
derground conductors  is  to  protect  the  insula- 
tion of  the  conductors  from  water  and  dirt. 
To  accomplish  this  in  the  present  conduit,  an 
angle  iron  is  riveted  to  the  top  flange  of  the 
channel  iron  in  such  a  manner  that  one  of  its 
flanges,  pointing  downward  parallel  to  the 
main  side  of  the  channel  iron,  forms  one  side 
of  the  slot.  In  the  inverted  trough  formed  in 
this  manner  the  conductors  are  fastened,  so 
that  the  contact  side,  i.e.,  the  side  on  which 
the  pieces  rub,  is  the  lower  side.  The  conduct- 
ors are  much  narrower  than  the  trough,  so  that 
contact  with  its  sides  is  impossible.  Dirt  or 
water  coming  in  through  the  slot  will,  there- 


the  latter  is  furthermore  to  protect  the  copper 
from  wear.  The  connection  between  the  con- 
ductors of  two  following  sections  is  made  in 
boxes  outside  the  conduit.  At  proper  intervals, 
the  top  of  the  conduit  is  made  removable, 
giving  access  to  the  inside.  These  traps  are 
also  put  at  every  place  where  a  connection  is 
made  with  a  manhole.  As  in  opening  these 
traps,  the  top  plates  are  often  handled  roughly 
and  thrown  in  the  dirt,  they  are  not  provided 
with  conductors,  but  in  place  thereof  wood  is 
fastened  to  them.  The  current  is  carried  round 
them  through  insulated  wires.  This  also  pre- 
vents interruption  of  traffic  in  case  of  the 
opening  of  a  manhole. 


FIG.  188. — THE  "  BERKSHIRE  "  ELECTRIC  CAR. 


fore,  also  fall  to  the  bottom  of  the  conduit 
without  interfering  with  the  insulation. 

The  conductors  are  made  shorter  than  the 
sections,  and  the  trough  is  closed  at  the  ends  of 
the  sections  by  means  of  a  block  of  wood  or 
other  insulation,  the  lower  side  of  which  is 
in  the  same  horizontal  plane  with  the  lower 
side  of  the  conductors.  These  latter  end 
within  about  i  to  J  inch  of  these  blocks.  In 
this  manner  the  insulation  is  protected  from 
any  dirt  or  water  coming  in  between  the  sec- 
tions. 

All  sections  are  made  exactly  the  same  size, 
so  that  if  one  is  damaged  it  can  easily  and 
quickly  be  replaced  by  another. 

The  conductor  itself  is  a  copper  bar,  to  the 
lower  surface  of  which  a  small  angle  iron  is 
fastened.  The  contact  pieces  rub  along  the 
iron  and  are  prevented  from  leaving  it  by  the 
downward  flange  of  the  angle.  The  object  of 


All  connections  between  the  conductors  of 
following  sections  are  easily  accessible,  so  that 
in  case  of  damage  to  one  section  this  can  easily 
and  without  interfering  with  the  conduit  be 
cut  out  of  the  circuit  and  the  current  taken 
round  it  by  means  of  insulated  wire.  As  the  sec- 
tions are  only  twenty  feet  long  at  the  utmost,  the 
momentum  of  the  car  will  easily  carry  it  over 
the  gap.  As  all  motors  on  the  cars  are  in  multi- 
ple arc,  no  complicated  make  and  break  appli- 
ances are  required  in  the  conduits,  and  as  the 
conductors  on  either  side  form  one  continuous 
line,  testing  for  insulation  and  continuity  can 
easily  be  done  from  the  station.  To  convey  the 
current  from  the  conductors  in  the  conduit  to  the 
motor  on  the  car,  each  of  the  latter  is  provided 
witli  specially  constructed  frames,  so  arranged 
as  to  make  the  contact  pieces  perfectly  inde- 
pendent of  the  oscillations  of  the  car  or  any 
variation  in  the  distance  between  the  body  of 


192 


THE   ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


the  car  and  conductors,  caused  either  by  vary- 
ing loads  on  the  former  or  uneven  construc- 
tion of  road-bed.  In  designing  these  frames 
great  care  has  been  taken  to  combine  simplicity 
with  strength,  the  vital  parts  being  well  pro- 
tected by  strong  cast-iron  or  phosphor-bronze 
frames.  On  the  road  now  running  in  Phila- 
delphia it  has  happened  several  times  that  large 
paving  stones  were  placed  intentionally  at  night 
on  the  conduit,  but  they  were  invariably  thrown 


ward  ;  and  by  moving  the  lever  more  or  less 
from  the  central  position,  the  speed  is  increased 
or  decreased.  If  desired,  levers  can  be  placed 
on  both  platforms,  the  one  not  in  use  being  se- 
cured by  means  of  a  lock. 

To  allow  the  motor  to  start  up  easily  and 
rapidly,  the  field  magnets  are  in  a  separate  cir- 
cuit which  is  not  opened  when  the  car  stands 
still.  The  motor  brushes  are  tangential,  one 
pair  only  being  required.  They  are  connected 


FIG.  189. — THE  SCHLESIXGER  ELECTRIC  CAR. 


to  one  side  by  the  frames  without  doing  the 
slightest  damage.  Steel  springs  are  used  as 
contact  pieces,  a  very  steady  and  good  contact 
being  thus  obtained,  as  shown  by  the  ammeter. 
The  motors  are  attached  to  the  cars  in  such  a 
manner  as  not  to  interfere  with  the  seating 
capacity.  They  are  placed  beneath  the  body  of 
the  car  between  the  axles,  and  specially  con- 
structed chains  transmit  the  power  from  the 
armature  to  the  wheels.  The  car  is  operated 
by  means  of  a  single  lever  on  the  front  plat- 
form. When  the  lever  stands  in  the  middle 
position,  the  current  to  the  armature  is  inter- 
rupted, and  the  motor  naturally  stands  still  or 
gives  no  power.  On  moving  the  lever  to  the 
right  the  car  runs  forward  ;  to  the  left,  back- 


with  the  lever  in  such  a  manner  that  the  same 
motion  by  which  the  current  through  the 
armature  is  reversed  also  sets  the  brushes. 
Aside  from  the  hand  brakes,  each  car  is  pro- 
vided with  electric  brakes  of  the  simplest  con- 
struction. The  interior  of  the  cars  is  lighted  by 
incandescent  lamps,  deriving  their  current  from 
the  same  source  that  propels  the  motor ;  and 
electric  gongs  complete  the  outfit. 

Among  the  most  prominent  of  the  electric 
motors  in  general,  practical  use  is  the  Edgerton, 
designed  by  Mr.  N.  H.  Edgerton,  of  Philadel- 
phia, and  shown  in  perspective  in  the  accom- 
panying engraving.  Fig.  190. 

The  pole-pieces,  Fig.  191,  are  arranged  each 
with  three  radial  cores,  on  which  the  exciting 


LATEST  AMERICAN   MOTORS  AND   MOTOR  SYSTEMS. 


193 


coils  are  wound,  and  by  which  the  fields  are 
supported  on  the  interior  of  a  cylindrical  iron 
shell  which  forms  the  framework  of  the  motor, 
as  well  as  the  yoke-piece  of  the  field  magnets. 


FIG.  190.— THK  EDGERTON  MOTOR. 

The  shell  and  pole-pieces  form  a  concentrically 
cylindrical  structure  in  the  interior  of  which 
the  armature  revolves  on  a  central  shaft  sup- 
ported at  either  end  by  bearings  situated  cen- 
trally in  the  end  caps  or  lids.  These  end  caps  may 
close  the  cylinder  entirely  or  not,  but  usually 
one  end  is  closed  completely  while  the  other  is 
left  open,  as  shown,  for  easy  access  to  the 
brushes  and  commutator. 

The  armature  shown  in  section  in  Fig.  101  is 
polar,  and  consists  of  three  helices,  wound 
upon  as  many  radial  cores,  set  at  equal  dis- 
tances upon  a  central  prism  of  the  same  num- 
ber of  sides.  Through  the  central  axis  of  this 
prism  the  shaft  is  placed  longitudinally,  and, 
as  before  stated,  supported  in  bearings  in  the 
end  caps  of  the  motor.  The  outer  or  peripheral 
extremity  of  each  of  these  cores  is  segmental 
in  shape,  coinciding  in  curve  with  the  inner 
concave  surfaces  of  the  pole  pieces  between 
which  it  revolves.  The  helices  are  wound  par- 
allel with  the  axis  of  the  armature  as  in  the 
Siemens  shuttle  armature,  and  each  is  complete 
in  itself.  Similar  ends  of  each  helical  wire  are 
connected  with  the  commutator  segments,  of 
which  there  is  one  for  each  helix ;  and  the 
other  similar  ends  are  carried  out  to  a  common 
union,  insulated  from  and  carried  upon  the 
shaft. 

It  has  been  the  aim  of  the  inventor  to  design 
his  motor  on  such  mechanical  lines  as  would 


insure  cheapness  and  simplicity  of  construction 
with  least  cost  of  maintenance.  To  this  end 
the  cylindrical  form  was  adopted,  as  it  fur- 
nishes bearings  of  the  greatest  solidity  and 
protects  completely  the  operative  and 
vital  parts  of  the  motor,  thus  allowing 
of  its  use,  without  injury,  in  the  most 
exposed  situations.  The  division  of  the 
field-magnet  coils  into  three  helices  for 
each  field  was  adopted  as  the  most 
likely  way  to  prevent  undue  heating 
in  the  motor  circuit,  in  addition  to  which 
the  shortness  of  the  cores  abutting  im- 
mediately upon  the  large  surface  of  the 
outer  shell  furnishes,  by  conduction  and 
radiation,  a  ready  means  for  the  dissi- 
pation of  all  such  heat. 

The  polar  armature  was  chosen  by  Mr. 
Edgerton  on  account  of  its  ease  of  con- 
struction, and   because   the    peripheral 
segments  of  the  spools   on    which    the 
helices  are  wound  make  it   impossible 
for  the  motor,  at  its  highest  speed,  to  displace 
any  of    the    wires    by    "tangential    inertia"; 
further,  because  in  the  rise  of  temperature  in 


FIG.  191. — SECTIONAL  VIEW  OP  EDGERTON  MOTOR. 

the  motor  due  to  flow  of  current,  while  in 
operation  the  coefficient  of  expansion  is  the 
same  both  in  armature  and  field,  which,  of 
course,  allows  of  the  rotation  of  the  armature 
in  closer  proximity  to  the  pole  pieces;  and, 
lastly  and  principally,  because,  according  to  Mr. 


194 


THE  ELECTRIC   MOTOR  AND   ITS  APPLICATIONS. 


Edgerton,  the  inductive  action  of  the  field  is 
received  first  by  the  iron  core  and  transferred 
through  that  to  the  wire,  thus  reducing  the  re- 
sistance of  the  armature  circuit,  due  to  counter- 
electromotive  force. 


FIG.  192. — THE  FISHEK  MOTOR. 

The  armature  is  connected  in  series  between 
the  fields  in  the  small  motors,  although  it  is 
perfectly  feasible  to  place  it  in  a  shunt.  When 
the  machine  is  coupled  in  series  and  in  opera- 
tion, the  current  is  active  at  all  times  in  two  of 
the  helices  and  momentarily  in  each  revolution 
in  all  three. 

In  the  smaller  sizes,  the  speed  of  the  motor  is 
regulated  by  means  of  resistances  included  in 
the  main  circuit  in  the  shunt  around  which  the 
motor  is  placed.  In  the  larger  sizes,  viz.,  from 
one  horse  power  and  over,  a  centrifugal  gov- 
ernor is  arranged  for  maintaining  a  uniform 
rate  of  speed.  With  this  size  also  the  armature 
and  commutators  are  changed  from  three  to 
five  segments  ;  while,  in  those  still  larger,  pro- 
vision is  made  for  one  brush  only  on  the  com- 
mutator, while  the  other  brush  is  transferred  to 
the  insulated  ring  of  the  bobbin  union.  As  all 
the  armature  bobbins  are  coupled  in  multiple 
arc  with  this  ring,  it  results,  as  a  matter  of 
course,  that,  with  the  commutator  slits  cut 
diagonally,  the  sparking  at  the  commutator  is 
reduced  to  a  minimum. 

It  has  been  the  rule,  as  evidenced  so  often  in 
the  preceding  pages,  in  the  construction  of 


electric  generators  or  motors,  to  so  adjust  the 
armature  with  respect  to  the  field  magnets  that, 
in  revolving,  the  bobbins  would  pass  trans- 
versely through  the  field  of  force  adjacent  to 
one  of  the  poles  and  then  transversely  through 
the  field  of  force  adjacent  to  the  other  pole. 
Recently,  however,  Mr.  Frank  E.  Fisher,  of  the 
Detroit  Electrical  Works,  has  devised  and  pat- 
ented a  modification  of  this  by  locating  the 
plane  of  revolution  of  the  armature  parallel  to 
and  between  the  two  planes,  each  of  which 
contains  one  of  the  field  magnets.  The  motor 
is  now  being  made  by  the  Detroit  Motor  Com- 
pany. The  opposite  ends  of  these  field  mag- 
nets are  then  united  by  a  pole  piece  extending 
from  one  across  to  the  other  in  such  manner 
that  instead  of  revolving  through  the  field 
adjacent  to  the  poles  respectively  the  armature 
is  caused  to  revolve  within  the  plane  containing 
the  poles  of  the  machine,  so  that  the  poles  are 
opposite  the  periphery  of  the  armature  and 
diametrically  opposite  each  other. 

Our  illustrations,  Figs.  192  and  193,  show  the 
new  design  in  elevation  and  in  plan,  and  are 
so  clear  that  no  further  description  is  deemed 


FIG.  193. — THE  FISHER  MOTOR. 


necessary.  According  to  Mr.  Fisher,  a  ma- 
chine, whether  motor  or  dynamo,  constructed 
in  this  manner  operates  with  very  much  less 
resistance,  and  consequently  delivers  a  greater 
effective  force  with  the  same  impelling  current. 
He  attributes  this  increased  efficiency  to  the 
fact  that  the  construction  is  such  that  the 


LATEST  AMERICAN  MOTORS  AND   MOTOR  SYSTEMS. 


195 


armature  revolves  diametrically  between  and 
in  the  plane  containing  the  poles,  instead  of 
being  obliged  to  cut  through  the  plane  trans- 
versely. Mr.  Fisher,  who  has  of  late  done  con- 
siderable studying  on  the  motor  question,  is 
also  of  the  opinion  that  a  beneficial  effect  in 
lessening  the  resistance  to  the  revolution  of  the 
armature  is  obtained  by  the  location  of  the 
armature  with  respect  to  the  poles,  so  that  its 
bobbins  shall  have  a  motion  first  transversely 
from  end  to  end  of  one  magnet  in  a  direction 
across  or  through  the  planes  of  its  successive 
convolutions  of  wire,  and  then  in  like  manner 
from  end  to  end  of  the  other  field  magnet. 

A  patent  issued  recently  to  Mr.  Elias  E.  Ries, 
of  Baltimore,  for  an  improvement  in  electrical 
railways,  is  of  timely  interest,  as  bearing  upon 
the  development  and  extension  of  electric 
street  car  lines. 

In  populated  cities,  as  is  well  known,  it  is 
necessary  that  the  conductors  employed  to  con- 
vey the  electric  current  to  the  motor  cars 
should  be  carried  in  an  underground  conduit, 
extending  along  the  line  of  the  railway.  As 
these  conductors  are  necessarily  naked  or 
partially  exposed,  in  order  to  permit  of  contact 
being  made  therewith  by  the  current-collecting 
devices  on  the  motor  cars,  one  of  the  chief 
difficulties  to  overcome  is  that  of  maintaining 
proper  drainage  facilities  and  preventing  water 
from  coming  in  contact  with  the  conductors  at 
low-lying  portions  of  the  roadway,  subject  to 
such  an  overflow  as  would  occur  in  case  of  un- 
usually heavy  rains,  or  from  the  accumulation 
of  water  in  the  conduit  arising  from  foreign 
matter  in,  or  back  flow  through,  the  drainage 
outlets,  etc. 


Mr.  Ries  overcomes  this  objection  in  a  simple 
and  effective  manner,  so  that  portions  of  the 
conduit  may  be  entirely  flooded  with  water  and 
the  conductors  therein  completely  submerged, 
without  in  the  least  interfering  with  the  flow  of 
current  to  the  motors  on  other  portions  of  the 
line.  This  result  is  accomplished  by  automati- 
cally cutting  out,  under  the  influence  of  the 
rising  water  in  the  lowest  portion  of  the  sub- 
merged conduit  section,  that  portion  of  the  con- 
duit conductors  belonging  to  the  submerged 
section,  and  shunting  the  current  through  in- 
sulated loop  conductors  or  cables  that  bridge 
the  section  cut  out  and  connect  the  main  con- 
ductors at  both  sides  thereof.  The  conduct- 
ors in  the  submerged  conduit  section  will  re- 
main cut  out  of  circuit  as  long  as  the  water  in 
the  conduit  is  of  sufficient  height  to  come  in 
contact  therewith ;  consequently,  no  escape  of 
current  from  them  can  take  place.  Means — such 
as  secondary  batteries — are  provided  for  auto- 
matically propelling  the  motor  cars  across  the 
low-lying  section  when  the  conductors  are  cut 
out,  so  that  it  will  be  seen  that  this  device 
renders  underground  electric-railway  conduits 
perfectly  practicable,  even  in  the  most  un- 
favorable localities,  and  goes  to  settle  once 
for  all  the  vexed  question  of  insulation,  but 
permits  the  successful  use  of  a  shallow  con- 
duit under  conditions  where,  without  this  de- 
vice, a  much  deeper  one  might  prove  entirely 
incapable  of  protecting  the  conductors  carried 
by  it. 

This  patent  also  describes  a  number  of  im- 
portant modifications,  and  forms  part  of  a  sys- 
tem of  electrical  railways  now  in  process  of 
development. 


CHAPTER   XIII. 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS— CONTINUED. 


AT  the  beginning  of  Chapter  XII.  it  was  re- 
marked that  great  activity  prevailed  in  the 
electric  motor  industry,  and  that  the  descrip- 
tions therein  were  to  be  taken  as  supplement- 
ary to  the  earlier  portions  of  the  present  work 
dealing  with  the  same  branch  of  the  subject, 
namely,  the  development  of  new  American 
motors  and  motor  systems.  The  activity  re- 
ferred to  continues,  and  may  even  be  said  to 
have  increased.  The  field  of  application  for 
motors  in  miscellaneous  stationary  work  has 
widened  immensely,  and  the  use  of  electric 
motors  on  street  railways  is  becoming  so  gen- 
eral that  the  employment  of  horse  or  cable 
appears  likely  to  cease  almost  entirely  at  an 
early  date.  Under  these  circumstances,  cer- 
tain additions  are  required  in  this,  the  second 
edition  of  the  present  work,  to  render  the 
record  of  invention  and  exploitation  measur- 
ably complete  to  date. 

Taking  up  the  subject  of  street  railways,  the 
first  ami  one  of  the  most  important  of  the  new 
systems  that  we  come  to  is  that  of  the  Bentley- 
Knight  Electric  Railway  Company.  The  pat- 
ents owned  by  this  company,  those  of  Edward 
M.  Bentley  and  Walter  H.  Knight,  have  especial 
reference  to  their  use  upon  the  city  street  rail 
way,  where  the  conductors  must  of  necessity 
be  supported  in,  and  protected  by,  sub-surface 
conduits ;  and  to  the  construction  of  an  elec- 
tric car,  the  mechanism  of  which  is  invisible 
and  inaudible  to  both  passenger  and  passer-by, 
in  which  the  passenger-carrying  capacity  is  not 
decreased  by  the  presence  of  any  part  of  the 
machinery  above  the  car  floor,  and  the  govern- 
ment of  which  is  effected  by  an  arrangement 
so  simple  as  to  permit  of  its  management  by 
the  ordinary  street-car  driver. 

From  the  time  that  its  first  experiments  in 
the  transmission  of  electrical  power  were  made 


at  Cleveland  in  1883-4,  under  the  auspices  of 
the  Brush  Electric  Company,  as  noted  in  earlier 
chapters  of  this  book,  the  Bentley-Knight  Com- 
pany's system  has  steadily  grown  in  efficiency. 
During  the  past  year  its  engineers  have  had  the 
assistance  of  the  Thomson-Houston  Electric 
Company,  of  Boston  and  Lynn,  Mass.,  in  the 
perfection  of  a  durable  and  reliable  railway 
motor,  and  of  the  Rhode  Island  Locomotive 
Works,  and  Messrs.  Nicholson  and  Waterman, 
of  Providence,  in  the  solution  of  mechanical 
problems. 

The  Bentley-Knight  Electric  Railway  Com- 
pany employs  the  constant  potential  system, 
the  pressure  remaining  constant  throughout 
the  line,  while  the  power  is  varied  by  the  cur- 
rent. Dynamos  giving  a  constant  electro  moti  v<- 
force  on  all  parts  of  the  line,  of  500  volts,  are 
used.  They  are  compound  wound  and  provided 
with  Professor  Thomson's  new  winding,  in 
which  the  main  circuit  field  coils  closely  sur- 
round the  armature,  and  oppose  the  tendency 
to  a  change  in  the  line  of  commutation  under 
varying  loads.  The  machines  have,  therefore,  a 
constant  lead,  and  require  but  casual  attention 
when  in  operation.  The  efficiency  of  the  motor 
per  se  is  90  per  cent.  The  current  strength  em- 
ployed is  about  7.5  amperes.  The  motor  will 
stand  30 amperes  indefinitely,  and  60 amperes  for 
half  an  hour.  Speed  is  controlled  by  a  coarse 
resistance  in  the  main  circuit  composed  of  iron 
plates  standing  on  edge.  The  motor  is  nearly 
self-regulating  within  the  limits  of  its  work, 
and  the  resistance  comes  but  little  into  piny. 
This  method  is  preferred  to  that  of  changing 
the  strength  of  the  field  magnet  independently, 
since  the  latter  necessitates  also  a  change  in 
the  lead.  The  position  of  the  brushes  is  never 
changed  either  for  varying  load  or  for  reversal. 
A  chain  from  the  resistance-lever  leads  to  tlie 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


197 


ordinary  brake-spindle,  and  is 
wound  thereon  oppositely  to  the 
brake-chain  so  that  the  whole 
control  is  centered  in  one  spindle. 
In  the  Bentley-Knight  system 
of  street  car  equipment,  the 
motor  and  all  its  attendant  me- 
chanism and  regulating  appara- 
tus is  mounted  upon  the  truck, 
is  wholly  independent  of  the 
car  body,  and  can  be  put  under 
any  existing  car  without  cutting 
or  alterations,  and  without  lift- 
ing the  car  above  its  normal 
height.  The  motor  is  placed  un- 
der the  car  floor,  outside  of  and 
overhanging  one  axle,  to  which 
it  is  geared,  being  counter-bal- 
anced by  a  spring  connection  ex- 
tending under  the  boxes  of  the 
opposite  axle.  Thus  the  whole 
weight  of  the  motor  comes  upon 
the  driven  axle,  and  a  small  part 
of  the  car  weight  is  also  trans- 
ferred from  the  free  axle  by  the 
leverage  which  the  motor  exerts, 
giving  ample  tractive  adhesion 
at  all  times.  This  arrangement 
also  ensures  a  rigid  connection 
between  the  motor-shaft  and  the 
axle,  which  is  essential  for  the 
proper  working  of  the  gearing, 
while  the  motor  has  a  spring 
support  and  a  yielding  impact 
on  the  road  at  starting,  making 
the  wear  on  working  parts  and 
on  the  track  very  light.  It  more- 
over permits  the  use  cf  a  coun- 
ter-shaft, and  a  ratio  of  gearing 
of  12  to  1.  The  efficiency  of  the 
electrical  transmission  is  propor- 
tionate in  a  measure  to  the  ratio 
of  gearing  permissible.  Tooth- 
gearing  is  used  throughout,  and 
all  journals  are  held  in  rigid 
castings.  The  brakes  are  hung 
from  the  truck,  not  from  the  car 
body,  and  there  is,  therefore,  no 
jarring  felt  by  the  passengers 
when  brakes  are  applied. 


198 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


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LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


10P 


The  motors  built  for  this  work 
by  the  Thomson-Houston  Com- 
pany have  cylindrical  armatures 
10  inches  in  diameter,  and  a  speed 
of  1,000  or  more  revolutions  per 
minute  is  perfectly  feasible.  The 
high  ratio  of  gearing  also  brings 
less  strain  on  the  bearings  of  the 
armature,  a  matter  of  importance 
where  efficiency  and  reliability  are 
required. 

The  car  is  stopped  by  shutting 
off  the  current  from  the  motor  and 
applying  hand-brakes.  The  only 
manipulation  necessary  is  by  the 
ordinary  brake  spindle,  as  de- 
scribed above.  Turned  in  one 
direction,  it  releases  the  brakes 
and  lets  on  the  current  in  suc- 
cession ;  and,  turned  in  the  oppo- 
site direction,  it  throws  off  the 
current  and  applies  the  brakes. 
The  spindle  works  within  two 
turns.  A  separate  lever  on  the 
dash-board  is  used  for  reversing. 
It  only  comes  into  play  when  a  car 
reaches  the  end  of  its  route. 

The  standard  truck  shown  in 
Fig.  194  is  one  of  those  built  for 
the  North  and  East  River  Railway, 
of  New  York  City,  the  tracks  for 
which  are  now  laid  through  Ful- 
ton street.  It  is  hoped  that  the 
legal  obstructions  which  have  pre- 
vented the  laying  of  the  conduit 
will  be  shortly  removed,  and  that 
this  road  will  be  in  full  operation 
in  the  near  future.  The  motor 
mounted  on  the  truck  shown  in  the 
illustration  will  give  from  fifteen 
to  twenty-five  horse-power  eco- 
nomically. The  very  heavy  curves, 
grades  and  traffic  of  Fulton  street 
necessitate  ample  provision  of 
power. 

The  illustration  of  the  car,  Fig. 
195,  shows  clearly  the  space  taken 
up  by  the  motor  in  actual  use. 
On  its  first  trial  trip  this  car  ran 
hours  on  a  total  consumption 


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THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


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LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


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THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


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of  1,680  pounds  of  coal  and  carried 
over  one  thousand  passengers,  run- 
ning on  a  bad  track  with  heavy 
curves  and  grades.  It  has  drawn  two 
full-size  loaded  passenger  cars  up  a 
7  per  cent,  grade  and  has  been  timed 
up  to  a  speed  of  28  miles  per  hour. 

Fig.  196  shows  the  very  powerful 
motor  trucks  which  have  been  fur- 
nished by  the  Bentley-Knight  Com- 
pany for  the  use  of  the  Observatory 
Hill  Passenger  Railway  Company,  of 
Allegheny  City,  Pa.  Fig.  197  shows 
a  car  mounted  upon  this  type  of 
truck.  The  grades  and  curves  of  this 
road  are  extremely  heavy,  the  heavi- 
est grade  being  9^  per  cent.  On  this 
maximum  grade  a  speed  of  six  miles 
per  hour  lias  been  regularly  made 
by  cars  loaded  with  over  fifty  passen- 
gers, while  on  the  approximately 
level  part  of  the  line  a  regular  speed 
of  15  to  18  miles  per  hour  has  been 
attained.  Neither  snow  nor  rain  has 
prevented  the  continuous  and  suc- 
cessful operation  of  this  line.  The 
cars  are  lighted  by  incandescent 
lamps  fed  from  the  motor  circuit, 
and  each  car  is  fitted  with  the  neces- 
sary contact  devices  to  operate  with 
both  sub-surface  and  overhead*  con- 
ductors, as  the  road  for  one-fourth  of 
its  length  is  equipped  with  a  con- 
duit, the  remaining  three-fourths  be- 
ing supplied  with  an  overhead  con- 
ductor system.  Fig.  198  shows  a 
motor  car  and  tow  at  a  conduit 
crossing. 

The  conduit  in  which  the  conduc- 
tors are  carried  forms  a  most  im- 
portant and  interesting  part  of  the 
system.  In  construction,  the  iron 
yokes  are  first  set  up  and  lined,  be- 
ing placed  from  three  to  four  feet 
apart.  The  continuous  gutter  is  then 
formed,  the  electrical  connections  be- 
tween the  lengths  of  conductor  are 
made,  and  the  slot-irons  set  on  the 
yokes,  their  braces  dropped  into  the 
exterior  lugs  of  the  yoke  and  the 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


203 


FIG.  201. — CONTACT  TROLLEY,  ELEVATED  CONDUCTORS. 


FIG.  200.— CONTACT  PLOW. 

duit  and  to  be 
readily  set  to 
close  either  cf 
the  branch 
slots  and  direct 
the  contact 
]>lo\v  into  the 
other.  A  corre- 
sponding con- 
ductor tongue  within  the  conduit  is  moved  at 
the  same  time.  The  strengthening  web  of  the 
heaviest  yoke  ex- 
tends only  fifteen 
inches  below  the 
level  of  the  pave- 
ment. 

The  method  of 
making  electrical 
connection  be- 
tween the  motor 
and  the  conduct- 
ors in  the  conduit 
— an  important 
point  —  is  clearly 
shown  in  Figs.  199 
and  200.  For  this 
purpose  a  contact - 
plow  is  employed, 
which  consists  of 
a  flat  frame  hung 
from  the  car  by  transverse  guides,  on  which  it 
is  free  to  slide  the  whole  width  of  the  car,  and 


slot-irons  and  yokes  firmly 
bolted  together,  leaving  a  sur- 
face opening  of  five-eighths 
of  an  inch.     The  two  main 
conductors  are  held  in  their 
places  by  heavy  lag  screws ; 
they   are  connected   by   ex- 
pansion  joints    and    are    of 
sufficient  size    to  carry   the 
current  with  but  small  loss 
of  energy.     Neither  the  traf- 
fic rails  nor  the  conduit  struc- 
ture form  any  part  of  the  electrical  circuit,  so 
that  there  is  a  double  provision  against  any 
contact  or  ground.     To  provide  for  switching, 
a  movable  tongue  is  pivoted  at  the  point  of 
branching,  so  as  to  rest  on  the  top  of  the  con- 


FIG.  202. 
ELEVATED  CON- 
DUCTORS SUP- 
PORTED BY  POSTS 
AND    BRACKETS 

AT  CURB. 


Fi(i.  203. — ELEVATED  CONDUCTORS  SUPPORTED  OVER 
CENTRE  OF   HOADWAY. 


extending  thence  down  through  the  slot  of  the 
conduit.     It  is  provided  with  a  swivel-joint,  so 

as  to  adjust  itself 
to  all  inequalities 
of  road  or  conduit. 
This  frame  carries 
two  flat  insulated 
conductor-cores,  to 
the  lower  ends  of 
which  are  attached 
by  a  spring  hinge 
small  contact-shoes 
of  chilled  cast-iron 
that  slide  along  in 
contact  with  the 
two  main  conduc- 
tors. At  the  upper 
ends  are  attached 
flexible  connec- 
tions leading  to  the 
motor.  This  plow 

can  be  inserted  or  withdrawn  through  the  slot 
at  will,  the  spring  hinge  allowing  the  contact- 


204 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


shoes  to  straighten  out  into  line  with  the  con- 
ductor-cores when  the  plow  is  pulled  upward 
and  the  shoes  strike  the  insulating  lining  with 
which  the  slot-irons  are  provided.  By  no 
accident,  therefore,  can  anything  be  left  be- 
hind in  the  conduit  to  obstruct  succeeding  cars, 
while  the  plows  may  be  pulled  out  at  will. 
The  plow -guides  are  hung  on  transverse  axes, 
and  are  held  in  a  vertical  position  by  a  spring- 
catch  that  gives  way  when  the  plow  meets  an 
irremovable  obstruction  ;  and  hence  the  plow 
is  automatically  thrown  completely  out  of  the 


as  to  prevent  leakage  of  the  electricity  from 
one  rod  to  the  other,  or  to  the  conduit,  have 
proved  entirely  unfounded.  From  practical 
experience  with  a  section  of  conduit  line  now 
in  operation  at  Allegheny  City,  Pa.,  it  is  as- 
serted that  the  leakage  is  inappreciable.  Care- 
ful measurements  taken  after  and  during  rain 
storms  which  lasted  for  days,  showed  no  loss 
whatever. 

Fig.  201  shows  one  type  of  trolley  for  use 
with  elevated  conductors.  Figs.  2;;2  and  203 
show  different  methods  of  supporting  elevated 


FIG.  204. — FIELD'S  ELECTRIC  LOCOMOTIVE — PERSPECTIVE. 


conduit  without  injury,  being  also  immediately 
replaceable.  The  contact-shoes  will  stand  weeks 
of  wear,  and  cost  very  little.  The  frame  of 
the  plow  has  wearing-guards  of  hardened  steel 
wherever  it  can  touch  the  edge  of  the  conduit- 
slot,  and  these  are  also  readily  renewable. 
Two  plows  are  used  on  each  contact  for  the 
sake  of  absolute  reliability,  and  to  prevent 
flashing  at  the  contact. 

The  doubts  which  have  been  expressed  in 
some  quarters  as  to  the  feasibility  of  properly 
insulating  the  copper  rods  in  the  conduit,  so 


conductors  now  in  use  by  the  Bentley-Knight 
Company. 

It  will  be  remembered  that  in  the  preceding 
chapter  a  description  was  given  of  the  electric 
motor  designed  by  Mr.  Stephen  D.  Field  to 
operate  upon  the  elevated  railroads  of  New 
York  City.  Some  experiments  with  it  have 
now  been  made.  The  locomotive  as  it  stood 
upon  the  track  of  the  Thirty-fourth  street 
branch  is  shown  in  the  accompanying  engrav- 
ing, Fig.  204.  The  motor  is  mounted  upon  the 
rear  truck,  and  the  distinguishing  feature  is 


LATEST  AMERICAN  MOTORS  ANT)  MOTOR  SYSTEMS. 


205 


its  mode  of  connection  with  the  drivers.  The 
arrangement,  as  will  be  seen,  is  exactly  similar 
to  that  employed  in  the  ordinary  steam  loco- 
motive, and  consists  in  the  direct  connection 
of  the  motor-shaft  with  the  drivers  by  means 
of  a  crank  and  side-bar.  The  great  advantage 
of  this  arrangement  in  the  electric  locomotive 
over  the  steam  locomotive  is  apparent  when  we 
consider  that  in  the  latter  the  maximum  effort 
is  exerted  on  the  drivers  when  the  cranks  stand 
vertically  either  above  or  be- 
low the  center,  and  when  on 
the  centers  no  effort  whatever 
is  exerted.  In  the  electric 
locomotive,  however,  the  arm- 
ature exerts  a  uniform  and 
continuous  effort  upon  the 
side-bar  which  is  transmitted 
directly  to  the  drivers,  no 
matter  what  the  position  of 
the  cranks  may  be.  It  fol- 
lows from  this  that  the  start- 
ing up  is  much  quicker  than 
in  the  case  of  the  steam  loco- 
motive, where  the  power  of 
only  one  cylinder  is  available 
at  a  time. 

The  motor,  which  is  series 
wound,  is  regulated  by  means 
of  a  liquid  rheostat  placed  in 
the  cab  of  the  locomotive, 
shown  in  Fig.  205.  This  rheo- 
stat consists  of  a  trough  di- 
vided into  two  compartments 
tilled  with  acidulated  water. 
A  metal  plate  on  either  side 
of  these  troughs  acts  as  a 
terminal  for  the  circuit,  which 
is  led  in  by  the  two  cables 
shown.  The  speed  of  the 
motor  is  regulated  by  inserting  or  withdrawing 
from  the  troughs  two  slabs  of  slate,  which  are 
suspended  over  the  troughs  and  can  be  raised 
or  lowered  by  means  of  the  long  lever  travel- 
ing over  the  sector  shown  at  the  right  in  the 
cab.  By  means  of  this  liquid  rheostat  the  re- 
sistance can  be  graduated  from  practically 
nothing,  •/.  e.,  when  the  slabs  are  fully  drawn 
up,  to  an  infinite  resistance  when  completely 
lowered  into  the  troughs.  On  the  standard 


which  guides  the  slabs  there  will  be  seen  a 
spring-clip,  and  on  the  right-hand  slab  a  plug. 
This  is  so  arranged  that  when  the  slabs  are  full 
up,  the  plug  presses  between  the  spring-clips 
and  cuts  out  the  rheostat  entirely.  The  revers- 
ing-switch  for  reversing  the  direction  of  the 
motor,  is  shown  in  the  lower  right-hand  corner 
of  the  cab. 

In  designing  the  locomotive,  Mr.  Field  con- 
structed special  brush-shifting  apparatus  for 


FIG.  205.— FIELD'S  ELECTRIC  LOCOMOTIVE— INTERIOR  OF  CAB. 


preventing  sparking  at  the  commutator  with 
change  of  speed  and  load.  This  consisted  of  a 
small  motor,  which  shifted  the  brushes  in  ac- 
cordance with  the  action  of  a  relay  in  circuit 
with  the  terminals  of  two  auxiliary  brushes 
placed  at  the  neutral  points  on  the  commuta- 
tor. Actual  practice,  however,  has  shown  that 
this  refinement  of  brush-regulation  was  unnec- 
essary, the  brush  lead,  under  the  influence  of 
the  peculiar  speed-regulation  employed,  having 


206 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


been  found  to  remain  fixed  and  at  an  angle  of 
45  degrees ;  this,  no  doubt,  being  due  to  the 
large  mass  of  iron  employed  in  the  construc- 
tion of  the  field  and  armature. 

The  following  table   gives  the  weight   and 
dimensions  of  the  locomotive  : 

Weight  of  motor 9  tons 

Weight  of  armature, 1  ton 

Weight  of  wire  on  armature, UOO  Ibs.  No.  7 

Weight  of  wire  on  field  magnets,  ....  1.000  Ibs.  No.  4 
Total  weight  of  motor,  ear  and  forward  truck,  ...  13  tons 

Diameter  of  drivers 3  feet 

Diameter  of  armature,  .- 2  feet 

Length  of  armature, 42  in. 

Wheel  base, 5  feet 


The  generating  plant  was  situated  at  a  dis- 
tance of  half  a  mile  from  the  track,  and  con- 
sisted of  a  single  dynamo,  built  by  Mr.  Rudolph 
Eickemeyer,  of  Yonkers,  in  whose  shops,  also, 
the  locomotive  was  built.  This  generator  is  of 
the  iron-clad  type,  and  showed  itself  fully 
capable  of  handling  the  load  placed  upon  it. 

The  tests  made,  which  extended  over  several 
weeks,  have  so  thoroughly  convinced  Mr.  Field 
of  the  practicability  of  the  new  ideas  embodied 
in  this  motor  that  he  has  been  prepari  ng  to  de- 
monstrate with  apparatus  on  a  large  scale  the 
practicability  of  electricity  as  a  motive  power 
for  the  elevated  railways  of  New  York  City. 


Fia.  206. — FIELD'S  ELECTRIC  STREET  RAILWAY — DOUBLE  CONDUITS  AND  TRACKS  COMBINED. 


The  track  on  which  the  motor  was  operated 
has  one  of  the  steepest  grades  in  the  city,  on 
which  account  it  was  peculiarly  well  adapted 
to  show  up  any  weakness  in  the  system  em- 
ployed. One  passenger  car  forms  a  load  for  a 
13-ton  steam  locomotive  regularly  employed. 

The  motor  easily  drew  one  of  the  regular 
coaches  up  this  grade  at  a  speed  of  about  eight 
miles  per  hour  with  a  current  expenditure  of 
35  amperes  under  an  E.  M.  F.  of  800  volts.  The 
loss  in  conversion  was  found  to  be  very  small. 

Various  potentials  were  at  times  employed, 
1,100  volts  being  used  at  one  time  with  the  same 
freedom  from  sparking  as  with  the  lower 
potential ;  the  only  change  noticed  being  an 
increased  speed  of  the  motor. 


Among  the  other  novelties  embodied  in  the 
motor  was  the  "pick  up"  wheel  of  Mr.  Field, 
already  described,  which  operated  admirably, 
so  that  no  sparking  whatever  could  be  observed. 

Finding  that  an  urgent  demand  existed  for 
efficient  electric  street  railways,  Mr.  Field  has 
also  turned  his  attention  in  that  direction.  He 
has  started  out  with  the  idea  of  reducing  the 
details  to  the  utmost  simplicity,  so  that  high 
potential  currents  can  be  carried  with  safety, 
and  that  the  position  of  the  motor  on  the  line 
shall  make  no  difference  in  the  potential  at  its 
terminals. 

Taking  up  the  mechanical  design  first,  it  will 
be  seen  from  Fig.  200,  which  is  taken  from  the 
actual  working  drawings,  calculated  on  the 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


207 


basis  of  a  ten-mile  road  with  100  cars  on  each 
track,  that  two  slotted  conduits  are  employed 
for  each  line  of  rails,  the  wheel  flange  running 
in  the  slot,  The  wheels  shown  are  30  inches 
in  diameter  and  the  conduits  themselves  are 
only  8  inches  high.  They  are  built  up  in 
lengths  from  two  sections  bolted  together  at 
the  bottom,  and  let  into  the  wooden  cross-ties. 
Heavy  ribs  are  cast  on  the  sides  of  the  sections, 
which  are  calculated  to  withstand  a  vertical 
pressure  at  any  point  of  16,000  pounds  to  the 
square  inch.  In  addition,  tie-rods  connecting 
the  upper  parts  of  the  conduits  lend  additional 
stiffness  to  the  structure  and  prevent  any 
spreading  or  closing  of  the  conduit  slots. 

It  will  be  noted  that  the  wheels  have  differ- 
ent treads  on  each  side  of  the  flange,  the  inner 
being  of  smaller  diameter  than  the 
outer  tread.  On  a  straight  track  the 
outer,  larger,  tread  of  each  wheel  bears 
on  the  track.  But  when  rounding 
curves,  the  wheel  bears  on  the  smaller 
tread  on  the  inner  rail,  so  that  it  has 
a  slower  motion  than  the  outer  wheel, 
and  thus  the  friction  usually  encoun- 
tered is  avoided.  The  angle-rails, 
which  are  bolted  to  the  tops  of  the 
conduits,  are  raised  only  one-fourth 
of  an  inch  above  the  level  of  the 
pavement,  and.  being  rounded,  pre- 
sent no  obstruction  to  ordinary  traf- 
fic. These  constitute  the  principal 
mechanical  details  of  the  road-bed. 
Special  provision  has  also  been  made 
for  drainage  of  the  conduits. 

The  electrical  methods  employed  by  Mr. 
Field  in  this  system  are  again  a  decided  depart- 
ure from  past  practice,  and  the  means  em- 
ployed in  carrying  out  the  system  are  unique 
in  conception.  In  Fig.  206,  it  will  be  noticed 
that  each  rail  conduit  has  supported  within  it 
a  conductor  carried  on  insulators.  The  con- 
nection of  these  conductors  with  the  source  of 
power,  the  dynamos,  is  shown  in  Fig.  207. 
Here  it  will  be  seen,  a  dynamo  vteking  one 
each  for  simplicity)  is  placed  at  each  end  of 
the  line.  At  one  end  (the  left  in  the  illustra- 
tion) the  positive  pole  of  the  machine  is  con- 
nected to  the  conductor  in  one  slot,  while  the 
negative  pole  of  the  machine  is  connected  to 


ground  ;  or,  what  is  the  same  thing,  to  the  iron 
of  the  conduit.  At  the  other  end  of  the  line, 
these  connections  are  just  reversed,  the  nega- 
tive pole  of  the  dynamo  being  connected  to 
the  conductor,  and  the'  positive  to  earth,  or 
the  conduit.  Now  supposing  each  dynamo 
to  give  250  volts  potential,  it  follows  that 
the  difference  of  potential  between  the  conduct- 
ors, and  hence  at  the  terminals  of  I  he  motor, 
will  be  500  volts.  The  circuit  is  made  from 
the  conductor  in  one  conduit,  through  the  mo- 
tor, to  the  conductor  in  the  opposite  conduit, 
being  completed  through  the  two  generators, 
conduits  and  axles  of  the  cars.  It  will  be  seen 
that  as  the  motor  recedes  from  one  generator, 
it  approaches  the  other,  so  that  wherever  the 
motor  may  be,  it  will  be  actuated  by  the  same 


-A 


FIG.  207. — FIELD'S  ELECTRIC  STREET  RAILWAY  SYSTEM. 


E.   M.  F.,   regardless  of  the  resistance  of  the 
conductors. 

The  switching  at  either  end  of  the  line  is 
accomplished  by  detaching  the  motor  from  the 
inside  conductor,  and  completing  its  circuit 
with  one  generator  only  from  the  outside  con- 
ductor to  the  conduit  direct,  thus  getting  the 
E.  M.  F.  of  only  one  generator.  At  the  same 
time  the  idle  contact  brush  passes  through  the 
path  of  the  inside  conductor,  which  is  removed 
for  that  purpose.  By  this  method  of  switch- 
ing two  objects  are  obtained.  In  the  first  place, 
the  motor,  by  working  on  the  lower  E.  M.  F. 
(250  volts,  instead  of  500),  passes  the  switch  at 
a  diminished  speed,  as  it  should. 


208 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


But  a  still  more  important  result  is  obtained 
by  the  use  of  the  two  conductors  connected 
in  the  manner  shown,  and  that  is,  that  all 
interruption  to  the  electrical  integrity  of  the 
conductors,  and  hence,  also,  the  traffic  of  the 
line,  is  avoided.  Thus,  each  car  will  be  pro- 
vided with  a  current  manipulator,  by  which 
the  motor  can  be  put  in  connection  with  either 
one  or  both  of  the  conductors,  as  it  is  evident 
that  each  one  forms  a  complete  circuit  by  itself, 
having  an  E.  M.  V.  of  250  volts  ;  but,  when 
combined,  they  give  a  difference  of  potential  of 
500  volts.  In  this  way,  all  track  switching 
devices  are  done  away  with. 

The  thorough  insulation  and  stability  of  the 
conductors  is  provided  for  by  the  manner  of 
their  suspension  and  attachment.  This  is 


Sue.HbrU.KK. 


FIG.  208. 

clearly  shown  in  Pigs.  208,  209  and  210,  which 
represent  longitudinal  and  transverse  sections 
and  a  plan  view  respectively,  of  the  arrange- 
ment. The  conductor  is  secured  to  a  steel  rod 
embedded  in  a  composite  insulator.  The  inner 
and  outer  shells  of  the  insulator  consist  of  hard 
rubber,  and  between  them  there  is  a  layer  of 
vulcanized  elastic  rubber.  The  whole  is  vul- 
canized together  so  as  form  one  piece.  By  the 
addition  of  the  softer  rubber,  the  conductor  is 
given  ascertain  flexibility  of  motion,  so  that  it 
can  follow  the  pressure  of  the  contact  brush 
without  undue  strain  on  the  insulator  supports 
or  pins.  At  the  joints  of  the  section  of  copper 
conductors,  a  flexible  bridge-joint  is  provided 
so  as  to  allow  for  the  expansion  and  contrac- 
tion ot  the  conductors. 


Mr.  Field  proposes,  also,  to  lay  pipes  in  the 
conduit  through  which  hot  brine  will  be  circu- 
lated in  winter,  so  that  all  snow  falling  into 
the  conduit  will  be  melted.  This  device,  of 
course,  need  only  be  put  in  operation  during 
extremely  cold  weather.  It  will  be  noted  that 


FIG.  209. 

the  conductors  are  placed  at  one  side  of  the 
slot,  so  that  any  dirt  or  snow  falling  into  the 
conduit  passes  clear  of  the  former.  No  extra 
appliances  for  cleaning  the  conduit  are  deemed 
necessary,  as,  being  only  8  inches  deep,  it  can 
be  easily  cleared  of  any  refuse  with  a  shovel 
let  into  the  slot,  and  by  means  of  which  the 
accumulation  can  be  removed  to  the  drains 
which  are  provided  at  short  intervals. 

The  street  car  designed  for  use  on  this  sys- 
tem is  shown  in  side  elevation  in  the  accom- 
panying illustration,  Fig.  211.  It  is  mounted 
at  its  front  end  on  the  usual  pair  of  wheels  arid 
axle,  but  at  the  rear  it  rests  upon  a  4  wheel 
bogie  truck,  so  that  the  car  can  turn  very  short 
curves.  Upon  the  same  truck  the  motor  is 
mounted;  it  is  geared  directly  to  the  wheels 
by  connecting  rods  attached  to  the  cranks  on 
either  end  of  the  armature  shaft.  The  lever  on 


FIG.  210. 

the  front  platform  is  connected  by  two  rods 
with  the  shifting  devices  on  the  motor,  and  a 
single  movement  is  sufficient  to  start,  reverse 
and  stop  the  motor,  and  to  connect  it  with 
either  conductor  in  the  conduits.  At  the  front 
end  of  the  car  two  plows  keep  the  slots  clear 
of  obstructions,  and  behind  them  the  contact 
arms  project  into  the  conduits. 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


2()9 


In  the  month  of  February,  1885,  a  company 
was  organized  in  Denver,  Col.,  under  the  name 
of  the  Denver  Electric  and  Cable  Railway  Co., 
for  the  purpose  of  building  and  operating  an 
electric  railway  in  the  streets  of  Denver.  It 
adopted  a  plan  proposed  by  Mr.  Sidney  H. 
Short,  then  Professor  of  Physics  in  the  Univer- 
sity of  Denver,  which  embraced  a  series  elec- 
tric railway;  and,  as  an  experiment,  a  short 
piece  of  track,  between  three  and  four  hundred 
feet  in  length,  was  laid  in  a  circle  in  the  Uni- 
versity grounds. 

A.  small  car,  named  "Joseph  Henry,"  was 
built  for  the  track  and  carried  many  hundreds 
of  people.  The  success  of  this  little  road  en- 
couraged the  company  to  make  more  extended 
experiments  in  this  direction. 


this  working  conductor  were  connected  by 
means  of  wire  with  the  dynamo.  When  a  car 
was  placed  on  the  track  and  had  its  brushes  or 
contact  springs,  one  on  each  of  the  parallel 
conductors  of  any  section,  the  electrical 
switches  at  each  end  of  that  section  would  at 
once  disconnect  one  of  these  conductors  at  one 
end  and  the  other  at  the  other  end,  leaving  the 
only  path  for  the  current  along  one  conductor, 
through  the  motor  to  the  other  conductor  and 
to  the  line  again.  These  sections  could  be 
made  any  convenient  length,  from  that  of  an 
ordinary  car.  to  a  block  or  a  mile.  A  car  could 
be  on  every  section  and  the  same  current  would 
pass  through  all  of  them. 

Mr.  Short  maintained  that  greater  economy 
in  electric  railways  was  to  be  had  bv  the  use 


Xi«.  wru.».  rTP 


FIG.  211. — THE  FIELD  ELECTRIC  STREET  CAR. 


This  first  road  was  built  on  the  following 
plan  :  Two  bare  conductors  were  laid  side  by 
side  along  the  track  in  a  small  conduit  placed 
between  the  rails.  The  conductors  were  small 
and  supported  on  insulators  attached  to  the 
cross-ties,  and  they  were  cut  into  sections  in 
order  to  test  the  working  of  the  system. 
Switches  operated  by  the  current  connected  the 
two  conductors  in  multiple  arc,  making  them 
practically  one  conductor,  having  the  conduct- 
ivity and  sectional  area  of  the  two.  These 
electrical  switches  at  the  same,  time  connected 
the  ends  of  the  sections  of  this  double  con- 
ductor, making  one  continuous  conductor  along 
the  entire  length  of  the  track.  The  ends  of 


of  a  constant  current  of  small  quantity,  by 
running  the  cars  in  series  like  arc  lamps  or 
telegraph  instruments,  and  varying  the  electro- 
motive force  with  the  power  required  to  operate 
the  line  of  road.  This  main  principle  has  not 
been  varied  from  since  the  beginning,  but  many 
modifications  of  the  details  of  construction 
have  been  made  from  time  to  time. 

The  two  conductors  used  in  the  first  arrange- 
ment were  intended  to  carry  the  current  in  the 
same  direction  at  the  same  time  along  the 
track,  and,  as  stated  above,  they  became,  elec 
trie-ally,  one  conductor.  At  the  junction  of  the 
two  sections  there  were  four  contacts  to  be 
operated  by  an  electrical  circuit-closer,  which 


210 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


was  necessarily  too  complex  and  delicate  a 
piece  of  mechanism  to  keep  in  good  working 
order,  especially  when  placed  on  the  street, 
where  it  was  liable  to  injury.  Mr.  Short,  there- 
fore, set  about  to  devise  some  means  of  com- 
bining the  two  wires,  in  order  to  do  away  with 
one  pair  of  contacts  at  the  junction  of  the  sec- 
tions, and  thus  to  lessen  by  one-half  the  chance 
for  leakage  from  the  insulating  supports.  He 
found  only  one  thing  to  do,  /.  e.,  to  shorten  the 
sections  of  the  conductor  to  the  length  of  one 
car  or  train  of  cars.  This  increased  the  num- 


means  for  keeping  the  spring  or  circuit-closer, 
shown  in  Fig.  212,  open  as  long  as  the  car  was 
over  it.  Mr.  Nesmith  proposed  that  a  long, 
slender  bar  of  insulating  material  be  stretched 
be 'ween  the  two  current-collectors  or  brushes, 
this  bar  to  slide  between  contacts  at  the  ends  of 
the  sections  of  the  conductor  and  keep  them 
apart  so  long  as  the  the  car  is  passing,  as  shown 
in  Fig.  218.  In  July,  1885,  this  second  plan  was 
tried  on  about  three  hundred  feet  of  track  with 
the  same  car  used  in  the  first  experiment.  A 
brush  at  each  end  of  the  car  made  contact  with 


RETURN     WIRE 


OTOfP" 


SECTIONAL     CONDUCTOR 

FIG.  212. 


her  of  circuit-closers  greatly,  but  at  the  same 
time  it  increased  the  flexibility  of  the  road,  as 
cars  could  be  run  as  close  together  as  they 
could  be  placed  upon  the  track.  On  this  plan 
a  contact  brush  must  be  placed  under  each  end 
of  the  car,  or  train  of  cars,  to  make  electrical 
connection  with  the  conductor,  so  that  there 
will  always  be  a  circuit-closer  between  these 
brushes,  as  shown  in  Fig.  212.  The  circuit- 
closer  between  these  two  brushes  must,  how- 


two  sections  of  the  conductor  and  a  leather 
strap  stretched  between  the  two  brushes  kept 
the  springs  apart  as  the  car  passed  over  the 
circuit-closer.  This  experiment  was  a  highly 
successful  one,  and  the  desired  end  seemed  to 
have  been  attained. 

The  Denver  Electric  and  Cable  Railway  Com- 
pany in  consequence  ordered  the  material  to  lay 
one-half  mile  of  track  upon  this  plan,  and  also 
two  motors  and  one  dynamo  of  the  Short  type. 


V X  £(«.  HirU,  A.  I- 

SECTIONAL    CONDUCTOR 


FIG.  213. 


ever,  be  kept  open  as  long  as  it  remains  be- 
tween these  brushes,  and  must  close  the  line  as 
soon  as  it  passes  from  between  them. 

Electrical  means  for  accomplishing  this  were 
devised,  but  were  open  to  the  same  objection  as 
the  one  referred  to  above,  and  with  the  large 
increase  in  number  this  objection  became  still 
greater.  It  thus  became  evident  that  a  me- 
chanical circuit-breaker  must  be  used.  Mr. 
Short  presented  this  plan  to  Mr.  John  W. 
Nesmith,  a  practical  mechanic  of  long  experi- 
ence, and  asked  him  to  devise  some  mechanical 


The  electric  conductor  used  in  this  trial  was  a 
slotted  copper  tube  of  about  1  inch  inside  diam- 
eter. Each  tube  was  about  16  feet  long  and  im- 
bedded in  asphaltum  and  tar.  The  whole  was 
incased  in  an  iron  shell,  and  a  slot  was  cut 
through  at  the  top.  These  centre  rails  were 
spiked  to  the  ties.  Between  the  ends  of  these 
sectional  conductors  were  mechanical  contact 
closers.  The  car  was  provided  with  a  contact 
brush  at  each  end,  which  fitted  into  the  tubular 
conductor  like  a  gun- wiper  brush.  Between 
these  brushes  was  stretched  a  long  flexible  rub- 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


211 


ber  cylinder  which  almost  filled  the  tube.  As 
the  car  moved  along,  the  forward  brush  was 
pushed  through  the  tube  and  contacts  at  the 
ends ;  the  rubber  rod  followed  and  kept  the  con- 
tacts apart  until  the  rear  brush  had  passed,  and 
the  current  Avas  forced  to  pass  from  one  brush 
through  the  motor  and  back  to  the  other  brush. 


rent-collecting  brushes,  and  mechanical  circuit- 
closing  springs  were  placed  at  intervals  in  the 
conduit,  as  before.  By  this  arrangement  it 
was  necessary  to  provide  careful  insulation 
onl}'  for  the  exposed  ends  of  the  sections  of 
the  conductor.  This  was  a  great  stride  to- 
wards success  with  the  conduit  system,  but  the 


FIG.  214. 


In  October  1885,  this  half  mile  of  track  was 
completed,  and  for  the  first  time  a  car  driven 
by  electricity  made  its  appearance  in  Fifteenth 
street,  in  Denver.  The  experience  of  a  few 
days  showed  this  plan  to  be  impracticable  on 


change  in  the  arrangemen  t  of  conductors  made 
a  new  device  for  connecting  the  current-collec- 
tors necessary.  This  was  accomplished  by  the 
construction  of  a  collecting  bar  shown  in  per- 
spective in  Fig.  214,  as  it  appears  when  be- 


account  of  the  difficulty  of  keeping  the  con- 
ductor insulated.  A  very  little  sand  and  dust 
in  the  tube  would  stop  the  brushes.  The  most 
serious  difficulty  to  overcome,  however,  was 
the  leakage  due  to  imperfect  insulation. 


FIG.  215. 

tween  a  circuit-closer  on  the  line.  Fig.  215 
shows  the  arrangement  of  the  bar  diagram- 
matically,  and  Fig.  216  is  a  diagram  of  the 
circuit  connections.  As  will  be  seen  from  Fig. 
215,  three  adjoining  sections  of  the  under- 


To  overcome  this  difficulty,  an  ordinary  un- 
derground cable  was  substituted  for  the  bare 
conductor.  This,  by  Mr.  Nesmith's  suggestion, 
was  laid  in  the  ground  outside  of  the  conduit, 


FIG.  216. 

ground  cable  are  connected  with  the  two  cir- 
cuit-closers, BB.  But  when  the  current-col- 
lector is  removed  from  the  circuit -closers,  the 
latter  are  in  contact,  and  the  line  is  continuous. 


leaving  the  conduit  for  the  passage  of  the  cur-     as  shown  in  Fig.  216. 


212 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


The  current-collector  is  made  of  a  slender  bar 
of  insulating  material,  somewhat  longer  than 
the  section  of  the  conductor  between  circuit- 
closers.  The  metal  strips,  1  and  2,  are  fastened 
around  the  entire  edge  of  the  bar,  except  at 
3  3,  where  there  are  short  insulated  breaks,  as 
shown.  Wires  pass  from  these  metal  strips,  1 
and  2,  to  the  motor.  The  current  passes  from 
section  5  to  metal  strip  2,  through  the  motor  to 
metal  strip  1,  and  thence  to  section  6.  The 
middle  section  of  the  conductor  4  is  cut  out  of 
circuit  when  the  current-collector  is  in  the  po- 
sition shown  in  the  figure.  If  the  bar  be 


and  mud.  The  tracks  were  flooded  and  the 
severest  possible  tests  were  made  to  prove  its 
merits  and  it  never  failed.  Upon  this  a  new- 
company,  the  United  States  Electric  Company, 
was  organized  in  August,  1885,  for  the  purpose 
of  developing  the  system.  In  June  and  July 
of  188J  this  new  company  put  down  under  con- 
tract 3,100  feet  of  an  electric  railway,  upon 
the  last  plan,  for  the  Denver  Electric  and  Cable 
Railway  Company.  This  track  was  laid  on 
Fifteenth  street,  between  the  Court  House  and 
the  Post  Office.  Ordinary  cross  ties  were  used, 
upon  which  were  strung  20-lb.  T-rails.  Notches 


FIG.  217. — CAR  ON  THE  DENVER,  COL.,  ROAD. 


moved  in  either  direction  it  will  be  seen  that 
no  flashing  can  occur,  nor  can  the  line  be  short- 
circuited.  This  current-collector  is  2£  by  1£ 
inches  in  section,  and  about  the  length  of  a 
car.  It  is  supported  in  the  conduit  by  attach- 
ments passing  down  through  the  slot.  In 
November,  1885,  the  company  put  down  on  the 
same  street  500  feet  of  the  new  line  of  insulated 
wire  for  one  of  these  current-collectors,  and  it 
worked  to  perfect  satisfaction.  During  the 
winter  of  1885  and  1886  this  short  line  was 
worked  in  all  kinds  of  weather,  in  &now,  rain 


were  cut  in  the  centre  of  the  ties  to  form  the 
conduit,  and  planks  were  spiked  to  the  ties  so 
as  to  cover  the  notches  and  to  make  the  slot. 
The  edges  of  the  .slot  were  protected  by  strap- 
iron. 

Under  one  of  the  planks  was  laid  a  Waring 
lead-incased  cable  of  No.  3  B.  &  S.  gauge. 
Circuit-closers  were  placed  every  25  feet  and 
the  cables  attached  to  them .  The  two  coaches 
built  in  Denver  were  placed  upon  the  track. 
Each  car  had  a  motor  of  the  Short  type,  made 
in  Denver,  and  was  supplied  with  both  revers 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


213 


ing  gear  and  speed  gear.  Eacli  motor  weighed 
about  1,500  pounds.  Tests  were  made  of  the 
efficiency  of  these  motors,  when  they  were  de- 
veloping from  five  to  eight  horse-power  with 
a  current  of  25  amperes,  and  they  showed  a  re- 
turn of  80  per  cent.  Our  illustration,  Fig.  217, 
shows  a  longitudinal  elevation  of  one  of  the 
first  two  cars  on  a  section  of  the  new  road-bed 
and  conduit. 

On  these  cars  the  motors  were  placed  on 
frames  which  were  hung  from  the  axles  of  the 
car  trucks,  and  carefully  insulated  from  them. 
On  the  armature  shaft  of  each  motor  was  placed 
a  rawhide  pinion.  This  pinion  drove  an  iron 
gear  on  a  counter-shaft  which  had  its  bearings 
attached  to  the  same  frame.  The  counter-shaft 
carried  another  pinion,  which  meshed  with  the 
large  gear  of  the  driving  axle  of  the  car.  This 
method  of  gearing  was  direct  and  positive, 


three  and  a  half  miles  were  soon  fully  equipped. 
A  new  conduit  of  cast-iron  is  used  on  this  line, 
and  is  shown  in  longitudinal  perspective  in 
Fig.  217  and  in  transverse  section  in  Fig.  218. 
The  slot  is  live-eighths  of  an  inch  wide,  and  the 
conduit  is  enlarged  to  9  x  12  inches  and  is  of 
substantial  construction.  The  new  truck  and 
gearing,  with  Brush  motor,  is  shown  in  Fig. 
219.  It  will  be  seen  that  the  ordinary  street 
car  wheels  and  axles  are  provided  with  an  iron 
frame  supported  upon  spring  pedestals,  upon 
which  the  motor  is  fastened.  On  the  shaft  of 
the  motor  is  a  pinion  which  drives  a  gear  wheel 
on  a  short  counter-shaft ;  the  latter  again  car- 
ries another  pinion  which  meshes  with  a  large 
toothed  gear  wheel  keyed  to  the  axle  of  the 
car  wheels.  The  greatest  ratio  between  the 
pinion  and  the  gear  is  1  to  5,  and  hence  very 
little  noise  is  made.  The  car  body  and  truck 


'111. 


\ 

1  u 


V'-';::/.--b-^:;:^' 
^''••'i£v'p;W'v^V 


*S$$ 

•V^i'-^VV;-? 
•-•^ii^aV^ 


I,  ,ll» 


PIG.  218. — CROSS  SECTION  OF  CONDUIT  AND  TRACK. 


made  little  noise,  and  admitted  of  a  simple  and 
efficient  reduction  of  speed  from  the  motor 
armature  shaft  to  that  of  the  car  axle. 

The  small  engine  and  dynamo  first  placed  in 
the  plant  were  used  to  furnish  the  power. 

On  the  31st  of  July  this  road  was  started,  and 
the  car  moved  from  one  end  of  the  track  to  the 
other  without  a  mishap.  This  road  was  run 
constantly  for  three  months,  two  men  being 
required  to  operate  it,  one  at  the  engine  and 
one  on  the  car. 

In  the  meantime  the  Denver  Electric  and 
Cable  Railway  Company  consolidated  with 
another  local  company,  and  the  new  association 
took  the  name  of  the  Denver  Tramway  Com- 
pany. This  company  contracted  with  the  Den- 
ver Tramway  Construction  Company  for  the 
equipment  of  its  lines  with  the  improved  sys- 
tem. The  work  was  immediately  begun,  and 


are  each  complete  in  themselves  and  are  put 
together  simply,  so  that  cars  that  are  now  being 
pulled  by  horses  can,  without  much  expense, 
be  adapted  to  the  electrical  system. 

The  conduit  shown  in  Figs.  217  and  218  is  so 
arranged  as  to  admit  of  its  being  put  down  on 
existing  horse-car  lines.  It  is  necessary  to  re- 
move the  pavement  only  in  the  centre  of  the 
track,  to  dig  a  trench  down  to  the  cross-ties 
and  to  put  down  the  cast-iron  conduit,  which 
is  made  complete  in  sections  of  8  feet.  Before 
the  pavement  is  relaid,  the  lead-incased  cable 
is  laid  along  at  one  side,  as  shown,  all  insulated 
and  complete.  The  change  from  horses  to 
electricity  is  made  in  this  way,  without  inter- 
fering with  the  regular  running  of  the  road. 

The  current  which  feeds  the  motor  is  used  to 
light  the  cars  with  incandescent  lamps,  and  to 
operate  an  alarm-gong  to  warn  persons  of  the 


214 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


approach  of  the  cars.  The  latter  can  be  moved 
backward  and  forward  and  governed  from 
either  platform.  According  to  Mr.  Sidney  II. 
Short,  to  whom  we  are  indebted  for  many  of 
the  foregoing  details,  indicator  cards  were  taken 
from  the  engine  while  three  cars  were  in  serv- 
ice. These  showed  an  average  of  32  h.  p.  de- 
livered to  the  driving  belt.  A  constant  current 
of  40  amperes  was  passing  over  five  miles  of 
No.  3  B.  &  S.  gauge  conductor.  The  resistance 
of  the  circuit  was  7  ohms  ;  hence  the  circuit 
alone  used  15  h.  p.,  which  left  17  h.  p.  for  three 
cars,  the  friction  of  belting,  shafting,  dynamo, 
etc.  This  gives  an  average  of  5.66  h.  p.  for 
each  car.  One  of  the  three  cars,  it  may  be 


of  an  inch  wide,  in  which  the  contact  wheel 
travels,  bearing  directly  upon  the  conductor 
within. 

Mr.  Fisher  employs  two  methods  of  attach- 
ing the  motor  to  the  car.  In  one  he  suspends 
the  motor  under  the  car,  and  in  the  other 
method,  which  is  illustrated  in  Fig.  220,  the 
motor  is  placed  on  the  front  end  of  the  car, 
which  is  inclosed  by  a  cab,  the  motor  man  act- 
ing also  as  a  conductor,  having  charge  of  the 
fare-box. 

The  length  of  the  road  is  3f  miles,  and,  being 
a  suburban  one,  comparatively  high  speeds' can 
be  attained.  Thus,  it  is  said  that  the  average 
speed  attained  is  18  miles  per  hour.  At  pres- 


FlG.    219. — MOTOK    AND    TKt'CK,    DENVEK    ELECTRIC    RAILWAY. 


added,  was  climbing  a  grade  of  360  feet  to  the 
mile  at  the  time  of  the  tests,  and  it  is  safe  to 
assume  that  it  was  using  one-half  the  power 
delivered  to  the  cars.  Hence  each  car  can  be 
run  at  the  expense  of  5  h.  p.  delivered,  after 
the  power  necessary  to  overcome  the  line  re- 
sistance has  been  deducted. 

A  road  has  recently  been  put  in  operation  at 
Detroit,  Mich.,  by  Mr.  Frank  E.  Fisher,  one  of 
whose  stationary  motors  is  'illustrated  on  page 
194.  As  will  be  noticed  from  Fig.  220,  current 
is  supplied  by  a  third  rail,  supported  upon  in- 
sulators placed  in  a  conduit  8  inches  square. 
The  conduit  has  a  slot  opening  three-fourths 


ent  there  are  running  on  this  road  four  cars 
equipped  with  motors  of  10  h.  p.,  giving  them 
sufficient  capacity  to  haul  an  extra  car  with 
full  load.  The  generating  dynamo  is  of  25,000 
watts  capacity,  and  delivers  the  current  at  a 
potential  of  500  volts  to  the  cars.  The  road 
has  an  extremely  neat  and  compact  station  at 
the  Detroit  City  end  of  the  line,  convenient  to 
the  railroad  from  which  fuel  supplies  are  ob- 
tained. 

While  it  is  acknowledged  that,  other  things 
being  equal,  a  conduit  for  the  conductors  is 
better  adapted  to  heavy  city  traffic  than  an 
overhead  system  of  conductors,  there  are  still 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


215 


Fio.  j>ao. — MOTOK  CAR  OK  THE  FISHER  ELECTRIC  KAILWAY. 


FIG.  221— FISHEK  ELECTRIC  MOTOR. 


216 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


some  who  object  to  the  slot  running  along  the 
street,  and  indeed  more  than  one  attempt  has 
been  made  in  the  past  to  avoid  the  use  of  the 
slot  and  to  establish  connection  with  under- 
ground conductors  by  other  means. 

In  attempting  to  solve  this  problem,  Mr.  W. 
E.  Irish,  of  Cleveland,  Ohio,  hit  upon  the  idea 
that  if  a  conductor  could  be  inclosed  in  an 


FIG.  222. — IRISH'S  ELECTRIC  RAILWAY  SYSTEM. 

elastic  conduit,  a  car  passing  above  it  might, 
by  pressure,  make  contact  with  the  conductor 
within  and  thus  establish  a  connection  ;  and 
this  connection,  made  directly  under  the  mov- 
ing car,  would  be  immediately  broken  when 
the  car  had  passed  on,  this  action  being  due  to 
the  elasticity  of  the  conduit. 

The  manner  in  which  this  has  been  carried 
out  is  shown  in  the  accompanying  illustrations. 
Here  Figs.  222  and  223  represent  the  arrange- 
ment adopted  by  Mr.  Irish,  in  section  and 


perspective.  As  will  be  seen,  A  represents  an 
elastic  or  yielding  conduit  of  soft  rubber,  which 
will  yield  to  the  pressure  of  the  contact  wheel 
and  react  with  sufficient  force  to  clear  the  con- 
ducting wire  when  the  pressure  is  removed. 

The  tube  or  conduit  is  closely  sealed  through- 
out its  length,  so  as  to  exclude  water  or  moist- 
ure and  to  prevent  metallic  contact  at  any 


point  except  through  the  proper  connections. 
A  channel  for  carrying  the  tube  is  .formal  in  P 
line  of  timbers  or  blocks  of  stone  B,  the  channel 
being  shown  as  having  flat  parallel  sides  and 
an  open  top.  The  timbers  or  blocks  carrying 
the  tube  are  laid  along  the  rail-post  track  be- 
tween the  rails,  flush  with  the  surface  of  the 
roadway,  two  lines  being  used,  one  to  carry  the 
outgoing  conductor  and  the  other  the  return 
conductor. 

The  tubes  A  carry  the  line  wires  or  conduct- 
ors C  at  the  bottom  of  the  oblong  track  therein. 
These  conductors  are  uncovered  and  uninsu- 
lated except  as  to  the  rubber  tube  A,  which 


FIG.  224. 

forms  a  covering  and  insulation,  so  that  con- 
tact may  be  made  within  the  tube  at  any  point 
in  their  length.  Attached  to  the  tube  along  its 
upper  surface  are  short  rail  pieces  D,  having 
small  flanges  at  their  sides,  which  rest  on 
shoulders  on  the  tube,  and  when  in  their  nor- 
mal position  are  flush  with  the  roadway  and 
top  of  the  timbers. 

Inside  of  the  tube  A,  and  corresponding  to 
the  rail  pieces  D  in  length,  are  contact  pieces 
E,  flanged  laterally  at  the  top,  and  having  a 
central  portion  which  rests  in  the  tube  above  the 
line  wire  or  conductor  C,  and  normally  out  of 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


217 


contact  therewith.  The  rail  and  contact  pieces 
are  insulated  from  each  other  by  the  rubber 
tube  except  where  they  are  connected  by 
screws,  by  which  they  are  firmly  united.  The 
short  rails  and  inside  pieces  are  arranged  in 
pairs,  and  the  pairs  are  insulated  from  each 
other  by  having  a  sufficient  space  between  them 
at  the  ends.  This  will  allow  one  section  or  pair 
to  be  depressed  without  interfering  materially 
with  the  next  on  either  side,  the  rubber  to 
which  they  are  secured  being  sufficiently  flexi- 
ble for  this  purpose. 


In  Figs.  224  and  225  //represents  the  contact 
wheels,  similar  in  construction,  one  of  which 
is  attached  to  either  side  of  the  centre  of  the 
car  and  electrically  connected  with  the  motor 
upon  the  same.  The  wheels  are  each  pivoted 
on  a  frame  or  turn-table  /,  which  is  arranged 
to  be  reversed  upon  the  car  according  to  the 
direction  the  car  is  to  travel,  and  to  be  raised 
or  lowered,  according  as  the  wheel  is  to  be 
thrown  into  or  out  of  contact  with  the  track. 
Pigs.  224  and  225  show  the  mechanism  by 
which  the  several  movements  are  effected. 
Thus  the  position  of  the  table  /and  its  attach- 
ments is  reversed  by  means  of  a  rod  K  rigidly 
fixed  thereto  and  having  a  crank  lever  at  the 


top,  and  it  is  raised  and  lowered  by  means  of  the 
tube  L,  which  is  provided  with  a  hand  wheel 
and  works  inside  the  sleeve  standard  which 
supports  the  parts  of  the  platform  on  the  car. 

The  contact-wheel  H  is  hung  in  a  pivoted 
frame  Non  a  shaft  on  which  it  has  some  lateral 
play  to  adapt  it  to  travel  on  a  track  that  may 
be  somewhat  out  of  alignment,  and  the  wheel 
has  a  concave  tread  which  enables  it  more 
certainly  to  keep  the  track.  P  is  a  tension 
spring,  bearing  upon  the  wheel  frame  .2V  with 
such  pressure  that,  as  the  wheel  passes  over 
the  sectional  track,  it  will  depress  the  sections 
successively,  so  as  to  bring  the  inside  pieces  E 
in  contact  with  the  main  wire  within  the  tube. 
The  wheels  //  act  alike  in  this  particular.  The 
moment  a  wheel  depresses  a  section  sufficiently, 
the  circuit  is  closed  through  that  section  ;  the 
screws  connecting  the  short  rails  and  the  inside 
contact  pieces  being  the  medium  for  the  pas- 
sage of  the  current  through  the  rubber  tube  ; 
and  as  one  section  is  not  cleared  before  connec- 
tion is  established  through  the  next  succeeding 
section  by  the  wheel  passing  from  one  section 
to  another,  the  flow  of  the  current  is  made  con- 
tinuous while  the  contact  wheel  is  down. 
When  the  sections  have  been  passed  by  the 
contact  wheel,  the  elasticity  of  the  rubber  car- 
ries them  successively  back  to  their  original 
position. 

The  conductors  in  the  bottom  of  the  rubber 
tube  are  coupled  together  in  sections  in  suita- 
ble lengths  by  means  of  a  variable  expansion 
joint  which  will  allow  of  expansion  and  con- 
traction under  varying  temperature  without, 
to  any  appreciable  degree,  altering  or  affecting 
the  electrical  resistance.  One  satisfactory  way 
of  doing  this  is  by  placing  a  sleeve  over  the 
ends  of  the  conductor  where  they  meet,  inside 
of  which  is  a  spiral  spring  which  bears  against 
the  ends  of  the  conductor.  This  spring  is  com- 
pressed by  the  expansion  of  the  conductor  and 
elongated  when  the  conductor  is  contracted, 
but  always  makes  effective  contact  with  the 
conductor  and  with  the  sleeve.  The  sleeves 
have  about  the  same  resistance  as  the  conduc- 
tor, but  the  contact  between  the  sleeves  and 
conductor,  or  line  wire,  is  more  or  less  imper- 
fect, and  this  imperfect  contact  is  made  up 
for  by  the  springs. 


218 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


In  front  of  the  contact  wheel  is  a  combined 
brush  and  scraper  Ji,  supported  upon  the  same 
frame  with  the  contact  wheel,  and  designed  to 
run  in  front  of  it  and  clear  the  exposed  section 
surface  rail  of  dirt,  snow  and  other  obstruc- 
tions, so  that  perfect  contact  may  be  made  with 
the  rail  or  track.  Connected  with  the  conduit 
described  above,  and  beneath  the  same,  is  a 
second  conduit,  Fig.  222,  of  cylindrical  form 
with  a  V-shaped  opening  longitudinally  in  its 
top  and  having  lateral  flanges  by  which  it  is 
bolted  to  the  timbers  or  blocks  carrying  the 
first-named  conduit.  The  conduit  is  de- 
signed to  carry  telegraph,  telephone,  electric 
light,  and  other  wires,  and  has  a  V-shaped 
covering,  underlaid  by  a  sheet  of  packing 
of  soft  rubber,  which  extends  laterally  over 
the  flanges  and  upper  conduit  timbers.  By 
unscrewing  the  top,  the  wires  can  be  reached 


FIG.  226. 

at  any  point,  and  the  tube  can  again  be  per- 
fectly sealed  by  screwing  the  top  into  position. 
One  of  the  methods  of  automatic  regulation 
devised  by  Mr.  Irish  is  shown  in  Fig.  226. 
This  consists  of  a  tube  having  a  concave  longi- 
tudinal section,  and  a  pivot  on  which  it  may 
be  adjusted  to  give  it  any  desired  inclination. 
As  shown,  the  tube  is  resting  in  a  horizontal 
plane,  and  this  throws  the  mercury  contained 
in  the  tube  into  the  centre.  The  series  of  wires 
c  d  extend  into  the  tube  and  make  connection 
with  the  corresponding  coils  on  the  field  mag- 
nets of  a  motor  D.  When  the  mercury  lies  as 
shown  in  Fig.  226,  all  the  coils  on  the  motor 
whose  wires,  c  d,  are  covered  by  the  mercury 
are  cut  out,  and  only  those  are  energized  whose 
wires  are  not  so  covered  and  connected.  The 


charging  of  the  field  magnets  and  the  amount 
of  electrical  energy  therein  is  therefore  under 
convenient  and  easy  control  through  the  tube. 
Obviously,  if  the  tube  be  tilted  to  the  left  it 
would  convey  the  mercury  forward  and  thus 
make  connection  with  one  set  of  contact  points 
after  another,  until  at  last,  if  carried  far 
enough,  the  entire  field  would  be  cut  out  and 
the  motor  would  stop.  On  the  other  hand,  the 
entire  energy  of  the  current  may  be  thrown 
into  the  motor  by  making  the  extreme  adjust- 
ment to  the  right,  and  relieving  the  contact 
points  of  the  connecting  fluid. 

The  motor  employed  by  Mr.  Irish  is  very  flat 
and  of  novel  design.  It  is  supported  under 
the  car  body  between  the  wheels,  and  is  so  ar- 
ranged that  all  or  any  part  may  be  examined, 
oiled,  or  replaced  from  the  inside  as  well  as 
the  outside  of  the  car  in  a  few  minutes.  The 
motor  shaft  is  furnished  with  two  armature 
coils  and  two  driving  wheels,  the  latter  being 
on  each  end  of  the  shaft.  The  maximum 
power  is  obtained  when  both  the  fields  and  the 
armature  coils  are  active,  although  the  car  can 
be  run  with  one  field  and  both  armature  coils, 
and  also  with  both  fields  and  one  armature 
coil,  or  with  one  armature  and  one  field  active. 

The  electric  railroad  in  the  Lykens  Valley, 
Pa.,  collieries  was  designed  by  Mr.  W.  M. 
Schlesinger  for  the  purpose  of  hauling  the  coal 
mined  in  the  upper  part  of  the  workings  out  of 
the  mine.  It  is  the  first  and  only  electric  mine 
railroad  built  in  America,  and  exceeds,  as  re- 
gards power  and  length,  any  of  those  built  in 
Europe.  The  following  table  shows  the  rela- 
tions between  the  different  roads : 


Where  Running. 

System. 

Length. 

Speed. 

Weight 

of 
locomo- 
tive. 

I.;irt;i-st 

weight 
pulled. 

Zankeroda  .... 

I'liulus  and 
Hohenzollern 
Lykens  Valley 

Siemens  and 
Halske.  .  . 
Siemens  and 
Halske.  .  .  . 
Schlesinger  . 

Feet 
2,028 

2.460 
(WOO 

.Mill's. 
6 

6 

Lbs. 
3,520 

4.200 
15.000 

Tons. 
13} 

ioo 

The  plant  in  Lykens  was  put  in  operation  on 
the  26th  of  July,  1887,  and  has  been  working 
without  trouble  ever  since,  hauling  with  ease 
trains  of  from  10  to  21  cars,  weighing  from  50 
to  100  tons,  according  to  whether  loaded  with 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


219 


ooal  or  rock.  As  soon  as  the  gangway  is  com- 
pleted and  the  works  open  up,  the  motor  is 
to  haul  from  200  to  250  cars  a  day,  or  bring  out 
from  900  to  1,125  tons  of  coal.  The  trains  are 
hauled  out  at  a  speed  of  6  miles  an  hour  (the 
maximum  speed  allowed  in  the  mines),  making 
the  round  trip,  with  necessary  stoppages  at  the 
termini  for  shifting,  in  from  25  to  30  minutes, 
whereas  it  took  the  mules  three  times  as  long. 
On  several  occasions  the  motor  has  already 
hauled  out  trains  at  a  speed  of  10  miles  an 
hour,  and  once  even  as  fast  as  15  miles  an 
Lour. 

Outside  of  its  greater  economy,  the  electric 
mine  locomotive  has  other  great  advantages 
over  the  steam  locomotive  and  over  mules  ; 
its  greatest  feature  is  the  entire  absence  of 
smoke,  steam  and  sulphur,  and  the  noncon- 
sumption  of  oxygen.  How  important,  especi- 
ally the  first-named  feature  is,  only  those  who 
have  been  in  gangways  in  which  steam  motors 
are  running  can  fully  understand  ;  and  it  is 
clue  to  this,  also,  that  the  electric  motor  can  be 
put  in  places  where  the  steam-engine  could  not 
be  used  ;  for  the  latter,  on  account  of  the  un- 
healthy gases,  etc.,  it  gives  out,  is  limited  to 
places  near  the  fans,  so  that  these  gases  are  at 
once  removed  from  the  mine,  as  it  is  dangerous 
to  allow  the  air,  after  once  having  passed 
through  the  steam  locomotive,  to  go  to  places 
where  men  are  at  work.  With  electric  motors 
this  precaution  is  unnecessary. 

As  regards  the  non-consumption  of  oxygen 
by  the  electric  motor,  it  saves  in  the  drift  at 
Lykens  20,000  cubic  feet  of  air  per  minute, 
which  would  be  required  for  a  steam  locomo- 
tive. But  outside  of  this,  another  great  ad- 
vantage of  the  electric  locomotive  lies  in  the 
fact  of  tluit  it  has  but  few  working  parts,  and 
that  these  can  be  got  at  with  the  greatest  ease. 

The  plant  in  Lykens  was  built  by  the  Union 
Electric  Co.,  of  Philadelphia.  The  drift  in 
which  the  motor  runs  is  one  of  the  upper  drifts 
of  the  Lykens  Valley  collieries,  the  entrance 
to  it  being  on  the  side  of  a  mountain.  Like  all 
gangways  it  is  higher  at  its  further  or  inside 
end,  but  the  average  grade  is  below  that  usually 
employed,  being  only  3  feet  in  100,  5  feet  in  100 
being  the  usual  grade.  In  most  places  the 
road  is  perfectly  level ;  there  are  three  or  four 


down  grades,  two  of  which  are  very  heavy,  and 
two  reverse  grades,  one  being  of  1-J  per  cent.,  up 
which  the  loaded  cars  have  to  be  hauled.  The 
road  outside  the  mouth  of  the  drift  is  about 
300  feet  long,  and  enters  the  mountain  on  a 
curve  having  a  105-foot  radius.  For  1,500  feet 
the  road  is  practically  straight ;  then  comes  an 
S-curve,  with  a  90-foot  radius,  and  a  series  of 
smaller  curves  up  to  2,400  feet  from  the  en- 
trance ;  the  next  half  mile  is  nearly  straight, 
but  at  the  end  of  it  is  a  90-degree  curve,  having 
a  30-foot  radius  ;  and  200  feet  further  is  another 
90-degree  curve,  with  less  than  a  25-foot  radius. 

The  siding  down  which  the  empty  cars  are 
taken  at  present,  so  as  to  be  out  of  the  way  of 
the  loaded  train  (or  trip),  is  between  these  two 
curves.  In  a  short  time  the  gangway  leading 
to  the  regular  turnout,  which  is  about  1,000 
feet  further  in,  will  be  completed,  and  the 
above-mentioned  siding  will  be  abandoned.  In 
coming  in  with  the  empty  cars  the  motor  finds 
the  loaded  ones  generally  standing  distributed 
on  the  curves  and  between  them.  The  motor 
has  to  collect  them  and  then  to  push  them  up 
a  1-per  cent,  grade  and  round  the  25-foot  curve, 
until  the  siding  for  the  empty  cars  is  cleared. 
This  is  the  heaviest  work  the  motor  has  to  per- 
form, especially  when  the  cars  are  loaded  with 
rock.  The  start  from  the  inside  is  always  made 
while  the  train  is  standing  on  one  or  the  other, 
or,  if  a  long  train,  on  both  these  curves.  The 
gangway  is  so  low  in  some  places  that  it  is  im- 
possible to  walk  upright. 

The  cars  in  use  weigh,  empty,  3,300  Ibs.,  and 
have  a  capacity  of  94  cubic  feet  each.  The 
wheels  are  18  inches  in  diameter,  and  run  loose- 
ly on  the  axles,  like  ordinary  wngon  wheels ; 
the  axles  are  rigidly  attached  to  the  car  body. 
The  result  is  that  very  soon  the  hole  in  the 
wheel  through  which  the  axle  passes  is  worn 
larger,  and  unless  carefully  and  frequently 
oiled  the  cars  run  very  heavy,  especially  as  the 
wheels  are  often  worn  oval  or  flat,  due  to  the 
insertion  of  sprags  to  prevent  the  cars  from 
running  away  down  hill,  and  to  stop  them 
when  mule  power  is  used.  The  heaviest  work 
performed  by  the  motors,  so  far,  was  at  one 
time  to  push  a  train  of  12  cars,  loaded  with 
rock  and  weighing  about  150,000  pounds,  up 
g-nde  round  the  25-foot  curve  ;  another  time 


220 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


a  train  of  twenty  cars  was  started  on  this 
curve,  only  three  cars  and  the  motor  standing 
on  or  beyond  it,  the  other  17  cars  standing  at 
right  angles  to  the  direction  in  which  the  mo- 
tor was  pulling. 

A  25-pound  rail  is  used  as  the  conductor, 
which  is  fastened  to  props  inclined  a  little 
from  the  vertical,  as  they  were  easier  to  put 
up  in  that  position.  About  half  way  between 
the  top  and  bottom  of  the  props,  and  mostly 
at  a  height  of  22  inches  above  the  track  and  15 
inches  to  the  side,  blocks  are  fastened,  and  to 
these  are  screwed  the  rails,  which  are  insulated 
by  rubber.  In  places  where  men  or  mules  have 


and  thus  throw  them  down,  without  in  the 
least  injuring  them.  In  not  one  single  in- 
stance was  any  one  of  these  miners  prevented 
froin  resuming  work  at  once,  nor  did  they  feel 
any  after-effects  from  the  shock.  The  joints 
in  the  rails  are  all  carefully  made  by  placing 
brass  plates  under  the  fish-plates  and  bolting 
these  down  tight,  so  as  to  press  the  brass  into 
all  the  uneven  parts  of  the  iron  rails.  The 
track  rails  are  used  as  the  return  conductor, 
and  these  are  connected  together  in  the  same 
way  as  the  conductor.  At  a  distance  of  every 
100  yards  the  two  track  rails  are  connected  by 
heavy  copper  wire,  so  that  repairs  can  be  made 


FIG.  227. — SCHLESINGER  MOTOR  FOR  LOCOMOTIVE  WORK. 


to  cross  the  conductor,  it  is  raised  to  a  height  of 
5  feet  9  inches,  and  recedes  to  24  inches  from 
the  track,  the  ascents  and  descents  being  made 
gradual.  Outside  the  drift  the  conductor  is 
5  feet  9  inches  high  all  along.  The  props  are 
placed  10  inches  apart  on  the  lower  side  of  the 
gangway,  so  as  to  be  out  of  the  way  of  the 
miners,  although  the  E.  M.  F.  used  (350  to  400 
volts)  is  not  dangerous.  As  an  instance,  sev- 
eral miners  have  already,  accidentally  or  pur- 
posely, touched  the  conductor  and  received 
shocks  from  the  same,  which  had  no  other  ef- 
fect than  for  the  instant  to  numb  their  legs 


to  the  road  while  the  motor  is  inside  without 
interrupting  the  current. 

The  engine-house  is  situated  at  the  mouth  of 
the  drift  on  the  side  of  the  mountain.  The 
steam-engine  used  is  an  old  one,  which  has 
in  been  use  in  the  mines  for  more  than  25  years. 
It  is  an  old  style,  long  stroke,  and  was  for- 
merly used  for  hoisting  purposes.  Since  it  was 
built  it  has  undergone  a  good  many  changes, 
so  that  at  present  the  steam-ports  are  entirely 
out  of  proportion  to  the  size  of  the  cylinder. 
This  engine  will  most  likely  be  soon  replaced 
by  another.  The  steam  is  conveyed  to  it  from 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


221 


boilers  1,000  feet  away,  and  a  great  saving  in 
power  might  have  been  effected  had  the  engine- 
room  been  placed  nearer  the  boilers  ;  but  as  a 
steam-pipe  passed  near  the  present  location  of 
the  engine-room,  it  was  thought  cheapest  to 
place  the  latter  near  the  entrance  of  the  drift. 
The  engine  is  run  at  a  speed  of  60  revolu- 
tions, and  from  a  9-foot  band  wheel  the  power 
is  transmitted  by  a  10-inch  belt  to  a  counter- 
shaft, from  which  the  power  is  transmitted  to 
the  generator.  This  generator  is  a  50  h.  p. 
series  wound  dynamo  of  the  Manchester  type. 
The  armature  is  of  the  dnim  type,  12  inches  in 
diameter,  and  makes  700  revolutions  per  min- 


is reset.  The  generator  is  at  present  in  charge 
of  a  boy  18  years  old,  who  also  acts  as  con- 
ductor to  the  train.  The  dynamo  has  been 
built  with  special  regard  to  efficiency  and  sim- 
plicity, its  main  feature  being  that  the  commu- 
tator can  be  replaced  by  an  ordinary  mechanic 
without  testing  instruments,  within  one  hour, 
and  without  the  possibility  of  a  mistake  being 
made. 

The  motor  represented  in  two  views,  in  Figs. 
227  and  228,  is  capable  of  giving  85  h.  p.,  and 
is  designed  especially  for  locomotives  having 
to  haul  heavy  loads.  It  is  27£  inches  broad, 
inches  long  and  22  inches  high,  and  weighs, 


FIG.  228.— SCHLESINGER  MOTOR  FOR  LOCOMOTIVE  WORK. 


ute.  The  commutator  is  placed  outside  the 
bearings  and  has  32  segments.  The  cores  of 
the  field  magnets  are  forged  out  of  picked 
scrap,  the  pole  pieces  being  of  cast-iron.  The 
whole  machine  weighs  1£  tons,  and  takes  up  a 
space  of  about  3|x5|  feet,  and  is  2|  feet  high. 
A  safety  cut-out  is  placed  on  the  dynamo, 
which  puts  a  large  resistance  into  the  circuit 
whenever  the  current  exceeds  a  fixed  limit, 
thus  reducing  it  and  preventing  the  destruc 
tion  of  the  generator,  as  well  as  motor,  arma- 
ture. A  large  gong  in  the  engine-room  rings 
whenever  this  safety  device  acts,  and  until  it 


with  counter-shaft  and  gear,  1,500  pounds.  The 
armature  is  of  the  Siemens  drum  type,  9J 
inches  in  diameter,  and  has  a  core  10£  inches 
long. 

The  wires  are  wound  within  troughs  fastened 
to  the  core  of  the  armature,  and  are  thus  pre- 
vented from  being  displaced  either  to  one  side 
or  the  other  by  the  pull  exerted  by  the  mag- 
nets on  them.  This  pull,  with  a  motor,  varies 
from  one  side  to  the  other  as  the  direction  the 
motor  runs  in  is  altered,  and  tends  not  only  to 
loosen  the  wires,  but  also,  by  causing  them  to 
move,  gradually  to  destroy  the  insulation. 


222 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


The  armature  makes  about  1,000  revolu- 
tions, the  countershaft  about  400.  The  bear- 
ings of  the  latter  are  part  of  the  same  frame  in 
which  the  two  armature  bearings  are  cast. 
This  keeps  the  two  shafts  parallel  under  all 
conditions,  and  insures  an  easy  running  of  the 
gears,  even  with  the  most  trying  alteration  in 
the  load.  After  six  months'  running,  the  teeth 
of  the  pinion  showed  a  wear  of  ^T  of  an  inch  ; 
i.  e.,  about  y£¥  of  an  inch  on  each  side  of  the 
tooth. 

The  32-part  commutator  is  placed  outside  the 
bearings,  and  is  constructed  in  such  a  manner 
that  it  can  be  taken  off  and  replaced  by  a  new 
one  within  an  hour  and  a  half,  it  being  unnec- 
essary to  disturb  any  of  the  other  parts  of 


FlO.  229. — SCHLESINGER  RAILWAY  MOTOR. — PLAN. 

the  machine,  or  to  make  any  electrical  connec- 
tion otherwise  than  to  solder  the  wires  into 
grooves  in  the  commutator  bars.  As  all  these 
wires  are  so  arranged  that  they  can  be  placed 
in  no  other  groove  than  the  one  to  which  they 
belong,  it  requires  no  electrical  knowledge  or 
training  to  accomplish  this.  The  position  of 
the  commutator  outside  the  bearing  has  the 
further  advantage  of  allowing  at  all  times  an 
easy  inspection  of  it  and  the  brushes,  and 
facilitates  the  proper  setting  or  adjusting  of 
the  latter. 

The  motor,  of  which  Fig.  229  is  a  plan,  is  se- 
curely fastened  by  eight  bolts  to  a  strong 
wooden  truck  having  30-inch  wheels  and  a 


wheel  base  of  40  x  40  inches.  The  truck  is  buil  t 
for  a  weight  of  15  tons.  The  motor  is  entirely 
boxed  in,  one  of  the  countershaft  bearings  and 
the  spur  wheel  passing  through  one  end  of  the 
box,  while  at  the  other  end  is  a  door  through 
which  the  commutator  can  be  reached  and  flu- 
brushes  set.  The  top  of  the  box  is  also  re- 
movable. On  either  side  are  large  compart- 
ments, well  braced,  for  the  placing  of  ballast. 
This  consisted  at  first  of  scrap  iron,  as  shown 
in  the  engraving,  Fig.  230,  but  now  iron  plates, 
2  inches  thick,  specially  cast  for  the  purpose, 
have  been  put  on.  The  seat  for  the  driver  is  at 
one  end  and  placed  sideways,  so  that  he  can 
run  the  locomotive  either  way  without  having 
to  change  his  seat.  With  his  left  hand  he  op- 
erates a  powerful  hand-brake,  and  with  the 
right  the  regulating  lever.  At  first  the  regula- 
tion was  effected  by  two  levers,  one  to  reverse 
the  motor  and  one  to  start,  regulate  the  speed 
and  stop  the  motor ;  but  now  both  these  actions 
are  performed  by  one  lever.  By  moving  it  out 
of  its  central  position  away  from  the  driver, 
the  motor  is  run  forward  ;  by  moving  it  toward 
the  driver,  it  is  reversed.  The  speed  is  regu- 
lated with  the  same  lever  by  means  of  resist- 
ance coils  placed  in  an  open  box  underneath 
the  foot-rest  for  the  driver. 

The  necessity  for  simple  means  of  operating 
the  car  is  obvious,  when  it  is  considered  that 
the  motor  runs  in  a  dark  tunnel  with  a  large 
number  of  sharp  turns,  and  the  walls  or  sides 
of  which  are  liable  to  give  way  at  any  moment, 
and  the  circumstances  being  such  that  a  break- 
down of  this  nature  is  generally  not  recogniza- 
ble until  the  motor  is  within  but  a  few  feet  of 
the  place.  An  electric  lamp  was  attached  in 
frojit  of  the  driver,  to  act  as  a  current  indicator, 
but  although  it  simply  hung  in  the  wires,  the 
jar  of  the  car  was  so  great  that  several  lamps 
were  broken  in  a  very  short  time.  A  plain 
ammeter,  consisting  of  a  solenoid  with  a  long 
pointer,  now  takes  its  place.  The  motor,  with 
ballast,  weighs  about  7£  to  8  tons. 

The  current  collector,  as  shown  in  Fig.  230, 
consists  of  a  frame  having  two  vertical  and 
two  horizontal  wheels.  In  this  frame  is  at- 
tached a  rod  which  passes  through  a  tube  and 
the  collector  is  pressed  against  the  conductor 
rail  by  means  of  a  strong  spiral  spring.  The 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


223 


tube  is  fastened  to  a  movable  arm  4  feet  long, 
attached  to  u  locomotive.  This  arm  allows  the 
collector  to  adapt  itself  to  all  vertical  inequali- 
ties of  the  rail,  while  the  tube,  spiral  spring 
and  rod  take  up  all  horizontal  variations  of  the 
rail.  This  collector  is  connected  directly  to 
the  switch-box,  and  the  return  current  passes 
partly  through  the  chains  and  partly  through 
small  shoes  rubbing  against  the  car  wheel,  then 


pecially  designed  for  the  purpose.  The  links 
are  made  of  phosphor  bronze  and  the  pins  of 
steel,  the  latter  having  a  wearing  surface  of  two 
square  inches.  From  the  second  countershaft 
to  the  car  axles,  steel  chains  with  thimbles  are 
used.  The  introduction  of  so  many  counter- 
shafts, of  course,  reduces  the  efficiency  of  the 
motor,  but  it  was  unavoidable  at  the  time  ;  it 
is  intended,  however,  to  alter  this  soon. 


Fiu.  230.—  LOCOMOTIVE  ON  THE  SCHLESINGER  ELECTRIC  ROAJI,  LYKENS  VALLEY  MINE. 


through  the  latter,  and  from  them  to  the  track 
rails.  In  addition  to  this,  to  prevent  sand  and 
dirt  on  the  track  interfering  with  the  running, 
metal  brushes  are  added,  which  either  run  con- 
tinually on  the  rails  or  can  be  pressed  against 
them  by  hand. 

The  chain  transmitting  the  power  from  the 
first  to  the  second  countershaft  has  been  es- 


The  engraving,  Fig.  231,  is  made  from  a  pho- 
tograph recently  taken,  and  represents  the 
motor  hauling  twenty  loaded  cars  and  one  pas- 
senger car  containing  six  persons. 

One  of  these  motors  has  been  running  for 
the  last  nine  months  in  the  Lykens  Valley 
Coal  Company's  mine  at  Lykens,  Pa.,  hauling 
daily  about  f)00  tons  gross  weight  over  a  road 


224 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


0,300  feet  long.  This  load  is  gradually  being 
increased,  ar.d  it  is  expected  to  haul  about 
1,000  to  1,300  tons  gross  weight  daily.  Some 
of  the  work  this  motor  has  accomplished  was 
to  haul  a  train  weighing  about  150  tons,  con- 
sisting of  31  cars  and  380  feet  long,  round  two 
curves,  the  one  having  a  radius  of  20  feet,  and 
the  other  30  feet,  and  the  distance  between 
them  being  180  feet.  This  same  train  had  after- 
wards to  be  started  while  standing  partly  on  a 


tons,  and  300  empty  cars  weighing  about  450 
tons,  so  that  the  total  load  of  this  motor  will 
be  nearly  2,000  tons. 

An  appendix  to  the  tirst  edition  of  this  work 
gave  a  description  of  the  Julien  accumulator 
and  traction  system,  which  were  being  in- 
troduced here  at  the  time  of  its  publication 
by  M.  Ed.  Julien,  engineer  and  electrician,  of 
Brussels.  Such  has  been  the  success  of  the 
demonstration  that  at  the  present  time  ten 


FIG.  231.— VIEW  OF  TRAIN  AT  THE  MOUTH  OF  THE  MINE. 


level  and  partly  (100  feet)  on  an  up  grade  of  15 
inches  in  100  feet.  The  average  number  of  cars 
hauled  by  this  motor  in  one  trip  varies  between 
10  and  20,  these  cars  being  partly  loaded  with 
coal  and  partly  with  rock  or  slate.  A  second 
motor  of  the  same  type  will  in  a  short  time  be 
in  operation  in  another  part  of  the  mine,  where 
it  will  have  to  haul  daily  300  loaded  cars, 
representing  a  gross  weight  of  about  1,500 


Julien  cars  are  building,  and  a  charging  station 
is  being  equipped  for  the  Fourth  avenue  road 
of  this  city.  The  Julien  car,  which  has  been  in 
continuous  service  for  some  months,  is  shown 
in  Fig.  232.  The  new  cars  will  be  of  different 
type  and  will  embody  many  improvements  in 
construction,  the  work  being  carried  out  by 
Mr.  C.  O.  Mailloux.  Various  other  trials  with 
storage  cars  have  been  made  in  New  York  and 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


225 


other  cities,  by  far  the  most  important  of  them 
being  those  made  by  Mr.  Anthony  Reckenzaun, 
at  Philadelphia,  for  the  Electric  Car  Company 
of  America. 

On  the  car  there  employed  are  two  Recken- 
zaun motors,  supported  by  two  small  trucks, 
similar  to  those  on  Mr.  Reckenzaun' s  street 
cars  in  Europe.  Each  motor  weighs  about  500 
Ibs.,  and  the  pair,  when  working  to  their  fullest 
capacity,  are  capable  of  giving  30  horse-power 
collectively.  Such  power  will  scarcely  ever  be 
needed,  but  it  can  be  called  into  requisition 
should  circumstances  demand  it.  The  car  has 
been  tested  on  the  experimental  line,  and  it 


street  car  in  the  world.  It  is  one  of  the  most 
carefully  designed  in  every  detail. 

The  frames  of  the  four-wheeled  trucks  are 
made  of  wrought  iron  ;  they  have  a  very  light 
appearance,  yet  they  are  of  ample  strength  to 
support  the  maximum  load  with  safety.  The 
wheels  are  only  26  inches  in  diameter,  which, 
when  revolving  at  103  revolutions  per  minute 
gives  a  speed  of  8  miles  an  hour  when  the 
motors  run  at  824  revolutions,  the  armature 
speed  being  reduced  8  to  1  by  means  of  Mr. 
Reckenzaun' s  worm  gearing. 

The  speed  of  the  car  is  regulated  by  a  switch 
which  causes  the  motors  to  work  in  series, 


FIG.  232.— THE  JULIEN  ELECTRIC  STREET  OAK. 


was  ascertained  that  the  current,  when  mount- 
ing the  grade  of  5|  per  cent.  (264  feet  to  the 
mile),  was  only  80  amperes,  and  on  the  level  25, 
and  this  current  was  supplied  by  74  storage 
batteries  ;  but  there  are  actually  120  cells  on 
board,  stowed  away  under  the  seats  on  long 
boards,  which  run  on  rollers  to  facilitate  the 
speedy  removal  and  replacement  of  the  whole 
battery.  The  seats  are  of  the  usual  height  and 
width,  but  they  are  22  feet  long,  accommodat- 
ing about  34  people,  so  that  with  the  available 
standing  room  and  platforms  a  hundred  pas- 
sengers can  be  crowded  into  the  car.  It  is  said 
that  this  is  the  handsomest  and  largest  electric 


singly  or  in  parallel  circuit,  so  that  all  the  cells 
are  always  used  when  the  car  is  in  motion, 
whereby  they  are  discharged  uniformly,  a 
result  which  will  be  appreciated  by  those  who 
have  had  experience  with  storage  batteries. 
The  cells  were  manufactured  by  the  Electrical 
Accumulator  Company,  of  New  York.  Large 
as  this  car  is,  it  goes  round  the  sharpest  curves 
with  remarkable  ease,  and  altogether  works 
well,  the  motion  of  the  whole  apparatus  being 
absolutely  silent. 

The  use  of  eight  wheels  removes  the  objec- 
tions raised  by  street  railway  men  with  regard 
to  the  additional  weight  of  storage  batteries,  so 


226 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


that,  by  distributing  the  load  over  8  points  on 
the  rails  there  is  no  need  of  providing  stronger 
roads.  Pivoted  trucks,  with  short  wheel 
bases,  facilitate  the  movement  round  curves 
very  much  ;  there  is  no  jerking  as  in  ordinary 
four-wheeled  cars,  and,  therefore,  the  flanges 
of  both  the  wheels  and  the  guard-rails  are  pre- 
served. In  the  large  car  under  notice  the 
wheel  base  is  only  three  feet  eight  inches. 


Turning  now  to  the  newer  stationary  motors 
brought  out  in  America,  the  first  that  claims 
attention  is  that  designed  by  Professor  Elihu 
Thomson  for  the  Thomson- Houston  Electric- 
Company,  and  whose  use  in  street  railway  work 
has  already  been  touched  upon.  For  sonic 
time  past  the  work  of  developing  a  line  of  elec- 
tric motors  suited  for  the  transmission  and  dis- 
tribution of  power  from  central  stations  and 


23-i.  —THOMSON  FIFTEEN  H.  P. 


MOTOII. 


The  use  of  four  driving  wheels  actuated  by  the 
positive  and  smooth  action  of  the  worm  gear 
offers  important  advantages  in  mounting  steep 
grades,  and  the  employment  of  two  distinct 
motors  (one  on  each  track)  decreases  the 
chances  of  an  absolute  stoppage  to  a  minimum, 
because  in  case  of  accident  to  one  machine  the 
other  is  sufficiently  powerful  to  bring  the  car 
home. 


for  other  purposes,  particularly  electric  rail- 
roading, has  been  carried  on  by  Professor 
Thomson.  The  object  held  in  view  was  to  con- 
struct machines  of  the  highest  lype  mechani- 
cally and  electrically.  Beginning  with  motors 
of  one  and  one  and  a  half  horse-power,  larger 
sizes,  up  to  full  fifteen  horse-power  capacity, 
have  been  rapidly  brought  out,  and  still  larger 
sizes  are  in  process  of  construction.  The  sizes 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


227 


now  built  are  one  and  one  and  a  half  horse- 
power, three,  five,  seven  and  a  half,  ten  and 
fifteen  horse-power.  The  motors  are  built  for 
constant  potential  circuits  of  110,  220,  400  and 
600  volts,  as  needed.  The  proportioning  is  such 
that,  supplied  with  a  constant  potential,  they 
are  practically  self-regulating  as  regards  speed, 
though  the  load  be  varied  from  nothing  up  to 
full  power,  or  the  reverse.  At  the  same  time 
the  brushes  on  the  commutator  run  without 
spark,  and  are  not  shifted  in  position  during 
extreme  changes  of  load  on  the  motor.  In 
other  words,  the  non-sparking  points  of  the 
commutator  remain  at  one  position  without 


arrangement,  and  the  field  magnet  coils  are  ir 
shunt  to  the  armature. 

The  armature. core  is  so  well  laminated  and 
the  resistance  of  the  armature  conductor  is  so 
low  that  loss  by  Foticault  currents  or  local 
currents  in  the  iron,  and  by  internal  resistance, 
is  very  slight  as  compared  with  the  output  of 
the  machine.  The  consequence  is  that  the 
motor  keeps  practically  cold  during  the  run- 
ning, and  is  capable  of  delivering  power  con- 
siderably in  excess  of  its  rated  capacity. 

Another  prominent  new  motor  is  that  de- 
signed by  Mr.  W.  Baxter,  Jr.,  for  the  Baxter 
Electric  Manufacturing  and  Motor  Company,  of 


FIG.  234.— SMALL  BAXTER  MOTOR  I-'OR  AKU  CIRCUITS. 


change,  notwithstanding  the  greatest  varia- 
tions of  load.  The  proportioning  is  such,  it  is 
claimed,  as  to  secure  the  highest  efficiency  of 
conversion  of  electrical  energy  into  mechanical 
energy.  Tests  have  shown  that  over  90  per 
cent,  commercial  efficiency  can  be  attained  at 
full  loud. 

As  will  be  noted  in  the  illustration,  Pig.  2'3'3, 
the  poles  of  the  field  magnets — the  bodies  or 
cores  of  which  are  round  in  section — project 
upward  and  inclose  the  armature,  the  section 
of  the  core  of  which  is  nearly  square.  The 
winding  of  the  armature  is  a  modified  Siemens 


Baltimore,  of  which  early  types  are  here  illus- 
trated. Fig.  234  shows  a  motor  of  the  smallest 
size,  built  for  arc-light  circuits,  and  intended 
principally  for  running  sewing-machines,  job 
printing-presses,  pumps,  fans,  etc.  When  in- 
tended for  pumps,  fans,  or  any  other  purpose 
where  a  constant  speed  and  power  are  required, 
it  is  made  without  the  ring  surrounding  the 
commutator  and  brushes  shown  in  the  illustra- 
tion. This  ring  is  only  used  when  the  nature 
of  the  work  is  such  that  the  motor  has  to  be 
started  and  stopped  very  often,  or  when  it  is 
necessary  to  vary  the  speed  at  will.  In  this  case 


228 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


the  brush-lever  is  made  movable  around  its  axis, 
and  the  electrical  connections  between  the  field- 
coil  terminals  and  brushes  are  maintained  by 
springs  attached  to  the  brush-holders,  and  so  ar- 
ranged that  their  free  ends  press  against  metal- 
lic linings  on  the  interior  surface  of  the  ring. 

A  spring  attached  to  the  upper  end  of  the 
brush-lever  holds  it  around  against  a  stop. 
When  in  this  position  the  brushes  are  raised 
off  the  commutator  and  no  damage  can  be 
done  by  turning  the  armature  backward.  At 
the  same  time,  the  contact-springs  that  press 


reaches  the  maximum.  Upon  the  wooden  base, 
and  underneath  the  armature,  is  a  switch  by 
which  the  whole  motor  is  cut  in  or  out  of  cir- 
cuit. These  small  machines  are  complete  in 
themselves,  and  require  no  auxiliary  attach- 
ment for  regulation.  The  commutators  are 
made  of  cast-steel,  and  are  calculated  to  last  for 
years.  The  journals  are  self-lubricating,  and 
will  run  for  weeks  without  attention. 

This  type  of  motor  is  made  in  three  sizes, 
namely  :  -fa,  -fa  and  T\  horse-power.  The  same 
patterns  are  used  in  all,  the  difference  in  capac- 


Fio.  235. — LARGE  BAXTER  MOTOR  FOK  ABC  CIRCUITS. 


against  the  interior  of  the  ring  are  in  such  a 
position  as  to  cut  out  the  armature.  The  mo- 
tor is  set  in  motion  by  rotating  the  brush-lever 
in  a  direction  opposed  to  the  tension  of  the 
spring.  The  first  movement  throws  the  brushes 
on  to  the  commutator,  so  that  the  circuit  may 
be  closed  before  the  armature  is  cut  in.  In 
this  position,  the  velocity  will  be  very  slow  ; 
but  as  the  lever  is  rotated  through  an  angle  of 
90  degrees,  it  gradually  increases  until  it 


ity  being  effected  by  winding  more  or  less  wire 
on  the  field.  Their  efficiency  ranges  from 
about  70  per  cent,  for  the  jij-,  to  65  per  cent,  for 
the  ^  horse-power.  This  efficiency  might  be 
considered  very  low  for  large  motors,  but  for 
motors  of  this  size  shows  good  design. 

Figs.  235  and  236  show  the  general  appear- 
ance of  the  larger  sizes  of  the  Baxter  motors. 
Fig.  235  is  a  constant  current,  and  Fig.  236  a 
constant  potential,  motor.  There  is  no  differ- 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


229 


ence  in  design  between  the  two,  but  the  method 
of  regulation  differs  in  each. 

The  constant  potential  machine  is  wound  so 
as  to  run  at  a  constant  speed,  but  as  the  same 
principle  cannot  be  applied  with  a  constant  cur- 
rent without  too  great  a  loss  in  efficiency,  a 
mechanical  governing  arrangement  is  used  in 
the  latter  type.  This  is  illustrated  in  Fig.  235. 
The  governor  proper  is  carried  on  the  outer 
end  of  the  shafft,  and  is  located  within  the 
shield  shown  in  front  of  the  motor.  The  de- 


highest  efficiency  is  between  one-half  and  two- 
thirds  the  full  capacity,  and  that  at  one-third 
and  full  load  is  about  the  same.  On  this  ac- 
count this  type  of  motor  is  well  adapted  to  a 
system  of  distribution  of  electrical  energy 
from  a  central  station. 

The  resistances  of  a  10-norse-power  motor  for 
a  1 0-ampere  current  are  as  follows  :  Armature, 
.75  ohm  ;  field,  3.75  ohms  ;  total  internal  re- 
sistance, about  4.5  ohms  ;  difference  of  poten- 
tial without  load,  45  volts  ;  total  difference  of 


FIG.  236. — LARGE  BAXTER  MOTOR  FOR  INCANDESCENT  CIRCUITS. 


vice  by  which  the  action  of  the  governor  is 
made  to  regulate  the  speed  is  located  on  top  of 
the  pole-plate.  The  principle  of  regulation 
consists  in  changing  the  magnetic  intensity  of 
the  field  by  a  variation  of  the  ampere  turns  in 
the  magnet  coils. 

With  this  system  of  regulation,  down  to  a 
certain  limit  the  efficiency  rises  ;  below  that  it 
begins  to  decrease  until  it  becomes  the  same  as 
at  maximum  load.  Practice  shows  that  the 


potential  of  motor  when  developing  10  horse- 
power, about  792  volts  ;  loss  by  internal  resist- 
ance, .0567,  or  a  little  more  than  5£  per  cent. 
There  are  two  layers  of  wire  on  the  armature, 
the  number  of  turns  being  320  ;  as  this  sets  up  a 
counter  E.  M.  F.  of  about  750  volts,  it  is  at  the 
rate  of  2.28  volts  per  turn.  Reducing  this  to 
work,  it  means  an  output  of  more  than  1,000 
foot-pounds  per  turn,  or  nearly  300  foot-pounds 
per  foot  of  wire. 


230 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


The  weight  of  wire  on  the  armature  is  about 
12  pounds  ;  weight  of  iron,  about  75  pounds  ; 
weight  of  wire  on  field,  about  160  pounds ;  iron 
in  field,  1,100  pounds.  These  figures  show  that 
a  very  small  amount  of  wire  is  used,  but  that 
otherwise  the  machines  are  very  massive.  On 
this  account  the  reaction  of  armature  on  the 
field  is  practically  nothing,  and  therefore  the 
brushes  require  no  lead  ;  hence  the  load  may 
be  varied  at  will  without  causing  sparking, 
as  the  diameter  of  commutation  remains  un- 
changed. 

The  Baxter  constant  potential  motor  is  almost 
identical  in  appearance  with  the  constant  cur- 
rent machine  just  described.  The  regulation 
is  accomplished  by  the  method  of  winding  ; 
hence  the  governor  and  its  attachments  are  re- 
moved ;  the  switch  is  also  replaced  by  simple 
binding-posts,  as  these  motors  are  provided 
with  an  independent  automatic  cut-out  and 
hand -switch  combined.  Constant  speed  is  ob- 
tained by  a  simple  shunt  winding. 

Prom  an  electric  standpoint  Mr.  Baxter  con- 
siders the  constant  current  method  of  distribu- 
tion to  be  the  better.  This  superiority,  he 
states,  is  not  due  to  any  defects  in  the  constant 
potential  motor,  but  is  owing  to  the  fact  that 
there  are  certain  advantages  in  the  constant 
current  system,  in  virtue  of  which  it  is  possi- 
ble to  obtain  results  that  are  beyond  the  reach 
of  the  constant  potential  system,  no  matter  on 
what  principle  the  motor  may  be  constructed. 

The  motors  manufactured  by  the  C.  &  C. 
Electric  Motor  Company  were  designed  to  meet 
the  demand  for  a  small  and  simply  constructed 
machine,  in  which  the  correct  principles  of 
dynamo  construction  were  not  all  violated.  It 
was  sought  to  make  those  elements  which  are 
known  to  be  the  essential  features  of  a  thor- 
oughly good  machine— high  circumferential 
speed  of  armature,  low  internal  resistance  and 
strong  magnetic  field,  etc. — the  first  considera- 
tion, and  then  to  design  shapes  and  invent 
methods  of  manufacture  which  would  enable 
the  electrical  requirements  to  be  carried  out 
most  cheaply.  The  result  of  careful  considera- 
tion of  these  things  has  led  to  the  construction 
of  a  motor  weighing  about  twelve  pounds,  and 
of  the  proportions  shown  in  the  engraving,  Fig. 
237,  and  which  is  made  on  the  American  plan 


of  automatic  machine  work  and  interchange- 
able parts,  to  a  degree  comparable  with  the 
manufacture  of  watches  and  other  well-estab- 
lished American  manufacturing  industries. 

Each  pole-piece  is  equal  in  cross-section  to 
the  core  inside  the  field-coil,  and  both  are  made 
of  one  piece  of  the  softest  domestic  iron  (Bur- 
den's Best),  with  the  fibre  running  lengthwise, 
or  in  the  direction  of  the  lines  of  force.  These 
cores  and  pole-pieces  are  made  from  round  bar- 
iron  of  the  size  of  the  core,  and  are  struck 
or  drop-forged  between  dies  having  exactly  the 
shape  of  the  finished  magnet,  even  including 


FIG.  237.— THE  C.  &  C.  MOTOR. 

the  small  lugs  on  the  outside  to  complete  the 
horizontal  support  for  the  field-coil  washers 
and  insure  a  true  winding  of  the  wire.  By 
the  process  of  drop-forging  the  inner  surface 
of  the  pole-piece  is  bent  around  a  rounded  part 
of  the  die  which  exactly  represents  the  space 
required  for  the  armature,  thus  insuring  a 
true  and  smooth  circular  space  for  the  latter. 
The  outside  of  the  forging  is  likewise  left  by 
the  die  smooth  and  finished,  and  the  irregulari- 
ties or  "fins"  are  all  brought  to  the  sides  of 
the  pole-piece,  where  they  may  be  trimmed  off 
by  the  same  trimming  operation  which  is  nec- 
essary to  make  a  seat  for  the  bearing-plates. 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


231 


Since  the  circular  space  for  the  armature  is 
the  important  thing  to  preserve,  all  of  the  fur- 
ther operations  of  cutting  and  fitting  the  forg- 
ings  and  of  assembling  the  motor  are  all  carried 
on  with  reference  to  this  circle.  The  forgings 
are  milled  off  bright  at  the  upper  end  to  re- 
ceive the  yoke,  the  forging  being  clamped  in  a 
vise  which  consists  in  part  of  a  round  iron 
block,  which  fits  into  the  concave  side  of  the 
pole-piece  and  represents  the  armature  space, 
and  which  is  set  at  a  fixed  distance  from  the 


FK;.  238.— THE  C.  &  C.  AUM.VITKK. 

milling  tool.  The  result  of  this  operation  is 
that  when  any  two  trimmed  forgings  are 
screwed  to  a  straight  yoke  in  the  usual  way, 
the  concave  portions  of  the  pair  will  agree  in 
forming  the  required  circle  for  the  armature 
space.  The  forging  is  then  clamped  in  another 
vise,  consisting  in  part  of  a  similar  round 
block,  and  the  two  edges  of  the  pole-piece  are 
trimmed  off  parallel,  so  as  to  bring  all  of  the 
pole-pieces  to  the  same  width,  a  straddle  cut 
being  taken  by  two  milling  cutters  mounted  on 
the  same  arbor.  The  forging,  which  is  thereby 
finished  to  gauge  in  all  respects,  is  next 
clamped  against  another  round  block  inside 
of  a  box  drilling-jig,  and  all  of  the  screw- 
holes  are  drilled  at  ore  operation  while  the 
forging  is  held  against  the  round  block  ;  so 
that  when  the  bearing-plates  and  other  parts 
are  screwed  on,  they  will  be  true  to  the  arma- 
ture space. 

The  field-coils  are  then  wound  between 
washers  driven  on  the  forgings,  and  the  field 
is  completed  by  screwing  to  the  top  a  yoke 
having  a  cross-section  equal  to  the  cores,  which 
gives  uniform  magnetic  conductivity  through- 
out the  frame.  Cast  or  stamped  brass  bearing- 


plates  are  then  screwed  to  either  side  of  the 
pole-pieces,  and  in  these  bearings  revolves  the 
spindle  or  shaft,  carrying  a  Gramme  ring  arma- 
ture, shown  in  Fig.  238. 

The  iron  of  the  armature-core  consists  of 
semi-circles  punched  from  thin  sheet-iron,  on 
one  side  of  which  tissue  paper  has  been  pasted 
before  punching.  These  semi-circles  are  laid 
together  with  the  ends  of  alternate  rings  pro- 
jecting at  either  edge  of  the  built-up  half-cylin- 
ders so  that  the  edges  of  the  two  half-cylinders 
so  formed  will  mate  together  or  interlock. 
The  half-cylinders  are  then  mated  together  at 
one  edge,  and  a  rivet  is  passed  through,  unit- 
ing them  like  the  parts  cf  a  hinge.  Upon  the 
split-ring  so  formed  is  slipped  a  fiat  helix  of 
wire  of  a  length  sufficient  to  form  the  entire 
winding  of  the  armature  and  consisting  of  only 
one  layer,  so  that  the  operation  of  slipping  it 
on  is  very  simple  ;  if  there  happens  to  be  any 
defect  in  the  insulation  it  can  only  short-cir- 
cuit or  render  useless  a  single  convolution  in- 
stead of  an  entire  section.  In  order  to  get  the 
required  E.  M.  F.  the  wire  used  is  flat,  as  shown 
in  Fig.  239,  and  wound  on  edge,  by  which 
means  it  is  possible  to  obtain  the  necessary 
number  of  convolutions  with  the  necessary 
conductivity  with  only  a  single  layer. 

By  this  plan  all  complication  due  to  unsym- 
metrical  winding  and  unequal  position  of  dif- 


Fm.  239.— THE  C.  &  C.  ARMATURE  WINDING. 

ferent  convolutions  in  the  magnetic  field  are 
avoided,  as  well  as  the  various  and  complicated 
inductive  effects  of  one  section  against  its 
neighbors  when  built  up  close  to  each  other  in 
a  good  many  layers  in  the  usual  way.  As  the 
winding  is  a  simple  or  progressive  helix,  none 
of  the  convolutions  overlap  each  other,  and 
consequently  there  can  De  no  serious  short- 
circuiting  ;  and  the  bad  inductive  effects  of  the 
current  in  one  section  running  in  the  opposite 


232 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


direction  to  the  current  in  the  other  sections  as 
the  coils  pass  the  point  of  commutation  are 
reduced  to  a  minimum.  In  addition,  this  wind- 
ing has  the  advantage  of  producing  a  mechan- 
ically balanced  armature,  as  it  is  obviously 
impossible  to  get  the  wire  wound  on  deeper  or 
in  larger  quantity  on  one  side  of  the  armature 
than  on  the  other.  The  flat  or  beam-shape  of 
the  wire  also  serves  to  stiffen  the  winding,  and 
prevent  its  flying  out  by  centrifugal  force,  thus 
rendering  a  circumferential  outside  lashing  un- 
necessary. As  the  number  of  convolutions  of 
wire  on  the  armature  is  of  great  importance  to 
the  efficiency  as  well  as  the  power  of  the  motor, 
great  attention  has  been  paid  to  this  point,  and 
a  ribbon  is  now  used  for  one  of  the  windings 
(type  E),  which  is  eleven  times  as  wide  as  it  is 
thick,  and  in  some  of  the  types  of  motor  is 
made  trapezoidal  in  cross-section  with  the  nar- 
row edge  out,  the  inclination  of  the  sides  of 
the  wire  being  sufficient  to  allow  the  sides  of 
consecutive  convolutions  to  lie  flat  against  each 
other  on  the  inside  of  the  ring.  By  doing  this, 
the  amount  of  copper  and  consequent  conduc- 
tivity is  slightly  increased  and  the  insulation 
is  better  protected,  since  it  does  not  bear 
against  the  insulation  of  the  next  wire  in  a 
single  line,  as  with  a  round  wire,  but  in  a  flat 
surface.  In  fact,  after  a  winding  is  in  place, 
the  entire  accessible  insulation  can  be  scraped 
off  both  inside  and  outside  the  rim  without  in- 
jury. 

This  winding,  which  is  shown  in  part  in  Fig. 
239,  is  wound  by  an  entirely  automatic  machine 
upon  a  flat  mandrel  equal  in  length  to  the  cir- 
cumference of  the  armature,  so  that  when  the 
mandrel  is  wound  full  with  one  continuous 
piece  of  wire  there  are  just  enough  turns  to  fill 
one  armature.  The  winding  is  divided  into 
seventeen  sections  by  seventeen  equally  distant 
convolutions,  which  project  about  a  quarter  of 
an  inch  farther  out  than  the  others,  and  fur- 
nish means  of  making  excellent  soldered  con- 
nections with  the  commutator.  In  forming  the 
winding  the  end  of  the  wire  from  the  reel  is 
fastened  to  a  suitable  catch  at  one  end  of  the 
mandrel,  which  is  then  started  revolving, 
the  wire  being  held  upright  or  on  edge  against 
the  mandrel  by  a  suitable  guide-arm,  which  is 
arranged  to  rise  and  fall  so  as  to  follow  the  sur- 


face of  the  mandrel  as  it  revolves.  A  large 
ratchet-wheel,  divided  into  a  number  of  teeth 
equal  to  the  number  of  convolutions  which  the 
armature  can  carry,  is  impelled  one  tooth  at  a 
time  at  each  revolution  of  the  mandrel,  and  the 
completion  of  the  revolution  of  this  index- 
wheel  automatically  stops  the  winding-machine 
at  the  moment  when  the  exact  number  of  con- 
volutions are  wound,  and  calls  the  attention  of 
the  operator  to  the  fact  that  the  winding  is 
completed.  The  projecting  convolutions  or 
loops  of  the  continuous  winding  which  mark 
the  termination  of  each  section  are  formed  in 
the  following  way:  a  ratchet-wheel  and  cam 
driven  by  the  revolving  mandrel  control  the 
movement  of  a  rounded  iinger  of  steel,  which 
slides  along  the  edge  of  the  mandrel,  and  is 
automatically  brought  directly  under  the  on- 
coming wire  at  the  instant  when  a  particular 
convolution  is  about  to  be  wound.  The  result 
is  that  this  convolution  is  wound  over  the  steel 
linger  and  made  correspondingly  higher  than 
the  rest.  The  finger  is  removed  instantly  by 
the  cam  at  the  moment  before  the  next  convo- 
lution begins  to  be  formed.  The  whole  opera- 
tion of  winding  a  complete  and  symmetrical 
armature  of  three  hundred  and  forty  turns  of 
wire  eleven  thousandths  of  an  inch  thick,  and 
one  hundred  and  ten  thousandths  of  an  inch 
wide,  and  transferring  it  from  the  mandrel  to  a 
wooden  spit,  occupies  eight  and  one-quarter 
minutes. 

The  commutator  which  consists  of  sector- 
shaped  pieces  of  copper  with  projecting  tails 
to  embrace  the  loops  above  referred  to,  is  se- 
cured by  taper-rivets  to  a  fibre-washer,  and  the 
latter  is  attached  to  a  wooden  block,  through 
the  centre  of  which  the  spindle  is  driven. 
This  block  is  forced  into  the  centre  of  the 
wound  armature  ring,  so  as  to  bring  the  com- 
mutator even  with  the  end  of  the  armature  and 
cause  the  high  convolutions  or  loops  of  the 
winding  to  project  between  the  tails  of  their 
respective  commutator  strips.  These  tails  are 
then  pinched  together  and  soldered  to  the  high 
loops,  the  insulation  having  previously  been 
scraped  off  the  wire  at  these  points. 

The  best  proportion  for  the  different  dimen- 
sions of  the  field-magnets  of  this  motor  were 
determined  by  building  a  magnet  of  approxi- 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


233 


mately  correct  design,  and  then  gradually 
increasing  the  diameter  of  the  iron  and  decreas- 
ing the  amount  of  copper  wound  on  it  and 
decreasing  the  length  of  the  iron  and  trying 
experimentally  the  effect  of  enlarging  the  mass 
slightly  at  different  points.  The  results  of 
each  change  were  noted  carefully,  and  but  a 
single  change  was  made  at  one  time,  so  that  its 
effects  should  not  be  confused.  By  this  pro- 
cess the  present  model  was  arrived  at,  and 
upon  comparing  it  with  some  of  the  latest  and 


tention,  with  the  recent  ideas  of  dynamo  con- 
struction ;  while  the  machines  with  which  it  is 
compared  are  some  of  the  largest  types.  The 
electrical  efficiency  of  the  machine  is  about  70 
per  cent.,  and  the  net  commercial  efficiency  has 
been  pronounced  by  prominent  electric-light 
engineers  who  are  using  it  to  be  about  55  per 
cent. 

The  machine  described  has  a  capacity  of  2,000 
ampere-turns  each  on  the  field  and  armature  ; 
that  is,  the  magnets  reach  the  best  point  of  sat- 


SCHKIH'LE    OK    TYPES    OF    C.    &    C.    MOTORS. 


Size. 

Power 
in  h.  p. 

Height 
in  inch's 

Weight 
Ibs. 

WINDING. 

A 

E 

F 

G 

L 

N 

20  am  p., 
for 
battery, 
or 
U.  S.  circuit. 

10  amp., 
or 
Brush,  etc., 
circuit. 

6%  amp. 
Thomson- 
Houston 
circuit. 

Field  in  mult, 
arc  for  signal- 
ing bells,  elec- 
tro-plating, 
etc. 

100  volts 
incandescent 
circuit. 

100  volts 
incan.  circuit 
for  constant 
running. 

( 

Field. 

Field. 

Field, 

Field, 

Field, 

Field, 

No.  10 

No.  12 

No.  14. 

No.  19 

No.  23. 

No.  23 

wire. 

wire. 

in  mult.  arc. 

extra  pull. 

No.  1 

Js 

7;V 

13     | 

Armature, 

Armature, 

Armature, 

At  mature, 

Armature, 

Armature, 

flat 

flat 

flat 

Hat, 

No.  27 

No.  27 

I 

wire. 

wire. 

wire. 

wire. 

wire. 

wire. 

Takes  J^  amp. 

Takes  %  amp. 

f 

Field, 

Field, 

1 

No.  10. 

No.  12. 

No.  3 

% 

10^ 

50 

Armature, 

Armature, 

I 

No.  l(i  wire. 

No.  19  wire. 

f 

Field, 

Field. 

No.  10. 

No.  12. 

No.  5 

1 

12J£ 

77 

Armature, 

Armature, 

I 

No.  16  wire. 

No.  18  wire. 

( 

Field. 

No.  10. 

No.  8 

2 

JBJ* 

127     \ 

Armature, 

I 

No.  15. 

most  efficient  dynamos,  embodying  the  latest 
and  best  ideas,  especially  Dr.  Hopkinson's 
latest  machine,  it  has  been  found  that  this 
little  machine  is  proportioned  almost  exactly 
like  the  large  Hopkinson  dynamo.  The  field 
in  both  cases  is  produced  by  from  500  to  600 
ampere-feet  of  winding  for  each  square  inch  of 
field-magnet  cross-section.  The  comparison  is 
interesting,  because  this  is  probably  the  small- 
est extensively  manufactured  motor  that  has 
been  made  in  strict  accordance,  as  was  the  in- 


uration  with  that  current.  As  a  great  many  of 
the  motors  are  used  on  constant  current  cir- 
cuits, and  the  various  commercial  circuits  differ 
in  current  strength,  it  was  necessary  to  make  a 
separate  class  or  type  of  winding  for  each  cur- 
rent by  varying  the  number  of  turns  so  as  to 
get  2,000  ampere-turns  on  either  circuit.  The 
size  of  wire  used  was  also  varied  inversely,  so 
as  to  produce  the  same  sized  coil  and  thereby 
maintain  the  same  efficiency  of  copper  in  each 
type. 


234 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


The  preceding  schedule  will  be  of  interest  to 
many,  as  showing  the  arrangement  of  sizes  and 
windings. 

The  windings  for  different  circuits  have  been 
designated  by  letters,  while  the  different  sixes 
of  motors  are  known  by  numbers. 


FIG.  240. — C.  &  C.  SHUNT- WOUND  MOTOR. 

Thus,  motor  type  1  E  No.  500  is  the  500th 
J-horse  power  motor  that  has  been  wound  for 
10-ampere  current ;  while  motor  type  5  A  No. 
10  is  the  tenth  1-horse  power  motor  that  has 
been  wound  for  20  amperes. 

The  C.  &  C.  motor,  illustrated  in  Fig.  240,  is 
shunt  wound,  so  that  it  runs  at  a  constant 
speed,  whether  running  free  or  heavily  loaded, 
and  it  is  belted  to  a  light  shaft  which  runs 
lengthwise  under  the  sewing  tables.  The  oper- 
ation and  speed  of  each  sewing  machine  is  con- 
trolled by  an  individual  treadle,  which  throws 
the  belt  of  that  machine  into,  or  out  of,  con- 
nection with  the  main  shaft  by  a  friction 
clutch.  This  arrangement  gives  to  each  ma- 
chine the  full  advantage  of  the  whole  power 
of  the  main  shaft  to  start  up  quickly,  so  that 
a  great  deal  of  working  time  is  saved  by  the 
operator  being  able  to  have  her  machine  started 
instantly  at  full  speed.  Though  the  load  occa- 


sionally put  upon  the  motor,  when  all  the  sew- 
ing machines  happen  to  be  in  operation  at  once, 
is  considerably  in  excess  of  the  rated  capacity 
of  the  motor,  and  though  again  at  times  none 
of  the  machines  are  in  operation  and  the  motor 
is  consequently  running  on  "no  load,"  its 
speed  never  varies  more  than  100  or  200  revolu- 
tions from  its  normal  speed  of  1,800. 

Fig.  241  is  also  a  ^-horse  power  motor  wound 
for  constant  speed  on  the  110- volt  incandescent 
circuits.  This  motor  has  a  resistance  of  about 
16  ohms,  runs  at  about  2,300  revolutions  with 
no  load  and  at  about  1,800  when  fully  loaded, 
at  which  time  it  takes  about  1^  amperes. 

The  iron  work  and  frame  are  the  same 
as  in  all  the  £-horse  power  motors  made 
by  the  C.  &  C.  Company  ;  but  the  winding 
is  new  as  applied  to  very  small  motors,  and 
is  identical  in  plan  with  the  winding  used 
on  the  largest  and  best  dynamos,  /.  e. ,  the 
field  is  fed  by  independent  connection  to 
the  line  wires,  and  is  thus  kept  at  con- 
stant strength. 


FIG.  241. — NKW  C.  &  C.  SHUXT-Worxu  MOTOR. 

The  armature  is  wound  with  about  3,000 
turns  of  wire,  so  that  the  counter  E.  M.  F. 
equals  the  direct  when  running  at2,300revolu 
tions.  A  very  slight  slowing  down  reduces 
this  counter  E.  M.  F.  enough  to  allow  the  full 
strength  of  current  to  enter  the  armature,  and 


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235 


therefore  the  motor  puts  out  its  full  power 
with  slight  decrease  of  speed.  The  switch  for 
stopping  and  starting  is  attached  to  the  motor, 
so  that  no  connections  to  a  separate  regulator- 
box  are  required. 


FIG.  242. 
('.  &  C.  MOTOR  WITH  WHEELKK  REGULATOR. 

The  motor  is  fitted  with  a  number  of  improve- 
ments, including  a  new  cylindrical  commutator, 
as  perfect  and  thoroughly  well  constructed  as 
those  used  on  the  largest  machines.  The  shaft 
can  be  unscrewed  and  taken  out  to  have  a 
longer  or  shorter  one  put  in  its  place.  In  set- 
ting up,  for  example,  to  drive  a  pump  in  a 
private  house,  the  motor  is  screwed  to  a  bracket 
near  the  pump  and  belted  to  it.  The  wires  are 
connected  to  the  binding  posts  at  either  side  of 
the  switch  knob,  and  the  apparatus  is  ready  to 
start.  The  action  of  the  knob  is  simply  to  send 
the  current  through  the  field  when  the  brass 
sector  reaches  the  first  spring  clip,  and  through 
both  armature  and  field  when  the  sector  touches 
both  springs. 

In  Fig.  242  is  shown  a  motor  provided  with 
the  Wheeler  regulator.  This  regulator  con- 
sists of  a  inulti polar  connected  armature  and 
field,  the  field  being  wound  in  sections,  which 
are  proportioned  so  that  they  will  divide  the 
main  line  current  with  the  armature,  always 
taking  that  percentage  which  will  give  the 


most  efficient  output  for  the  machine  afforded 
by  the  condition  of  running,  as  determined  by 
the  speed  switch.  This  switch  is  connected  so 
as  to  be  simply  the  means  of  short-circuiting 
more  or  less  of  the  coils  of  the  field.  In  this 
way  the  current  flowing  through  the  armature 
is  also  controlled,  without  having  actual  access 
to  the  armature.  The  paths  for  the  current  of 
the  arc  light  circuit  between  binding  post  and 
binding  post  of  the  motor  are  through  the 
brushes  and  armature,  through  the  coils  of  the 
field,  and  through  the  short  circuiting  switch 
and  the  coils  of  the  field  which  are  not  short- 
circuited.  There  are  thus  three  paths  for  the 
current,  and  there  is  absolutely  no  danger  of 
injury  from  the  accidental  opening  of  any  one 
of  these  paths. 

The  small  £-horse  power  motor,  shown  in  Fig. 
243,  is  interesting  as  being  also  made  with  a 
complete  regulator.  A  further  advance  has 


FIG.  243. 

been  gained  in  this  smallest  machine  by  fitting 
it  with  a  cylindrical  commutator  in  all  respects 
like  those  used  on  larger  sizes.  The  armature 
core  is  supported  by  brass  spiders  in  to  which 
the  shaft  is  screwed,  overcoming  the  difficulty 


236 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


of  an  unbalanced  armature,  and  producing  a 
perfectly  interchangeable  machine  in  motors  to 
be  used  continuously  on  power  lines.  The 
bearings  also  are.  made  heavier. 

Quite  recently  Dr.    Orazio    Lugo,    of  New 
York,  has  constructed  a  motor  which,  though 


FIG.  244.— THE  LUGO  MOTOR. 

resembling  some  older  types  in  appearance, 
nevertheless  possesses  some  decidedly  novel 
features. 

The  new  motor  of  Dr.  Lugo  is  designed  to 
utilize  the  maximum  effects  found  in  placing 
moving  solenoids  in  proximity  to  fixed  sole- 
noids in  such  relation  that,  as  the  armature 


FIG.  244A. — THE  LUGO  MOTOR. 

coils  move,  a  maximum  number  of  lines  of 
magnetic  forces  is  cut  in  the  passage  of  each 
armature  bobbin  past  each  field  magnet  bobbin, 
and  these  effects  are  made  successive,  so  that 
there  is  a  continued  application  of  such  suc- 


cessive effects.  And,  in  addition  to  utilizing 
these  effects,  due  to  a  specified  relation  of  the 
solenoids  themselves,  the  combined  effects  of 
Ihese  solenoids  and  their  cores  also  are  em- 
ployed. 

By  creating  successive  magnetic  circuits 
through  successive  armature  and  field  bobbins 
in  pairs,  until  the  series  has  been  gone  through 
once  in  each  complete  i  e vol  u  rion  of  the  armature, 
each  armature  bobbin  being  in  circuit  at  least 
once  in  a  complete  revolution  with  each  field 
magnet  bobbin,  and  all  of  the  bobbins,  both  of 
the  armature  and  field  magnets,  being  allowed 
to  rest  magnetically  by  being  cut  out  of  circuit 
during  a  fraction  of  each  revolution  of  the 
armature,  the  evil  effects  of  Foucault  currents 
are  said  to  be  largely  avoided. 

The  motor,  which  is  of  very  simple  construc- 
tion, is  shown  in  perspective  in  Pig.  244  and  in 


FIG.  244B. — THS  LUGO  MOTOR. 

cross-section  in  Pig.  244A.  As  will  be  seen,  it 
consists  of  a  series  of  bobbins  arranged  in  a 
circle  to  the  number  of  five,  and  within  which 
there  revolve  four  similar  bobbins  attached  to 
the  shaft  of  the  motor.  All  these  bobbins  arc 
provided  with  cores  and  short  pole  pieces, 
which  revolve  in  close  proximity  to  each  other. 
The  revolving  armature  coils  are  connected 
to  a  commutator  fixed  to  the  shaft,  upon  which 
bears  a  stationary  brush  S\  shown  in  the  end 
view,  Fig.  244u.  The  connections  of  the  indi- 
vidual armature  bobbins  to  the  commutator  are 
seen  in  Fig.  244c,  which  shows  also  the  cross- 
connection  between  the  coimnutator  strips. 
The  other  side  of  the  armature  shaft  carries  a 
revolving  brush,  which  bears  against  a  fixed 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


237 


commutator  to  which  the  lield  bobbins  are  con- 
nected. This  is  shown  in  the  end  view,  Pig. 
244i>,  and  the  commutator  in  detail 'in  Fig.  244K. 
Finally,  Fig.  244F  shows  the  circuits  diagram - 
atically,  with  the  bobbins  laid  side  by  side, 


FIG.  244c. — THE  LUGO  MOTOR. 

and  showing  the  manner  of  their  connection 
one  with  the  other. 

It  will  now  be  readily  understood  that  if  a 
current  be  passed  through  the  armature  and 
field  bobbins  M2,  F2.  the  pole  pieces  are  in 
such  a  position  as  to  cause  M2  to  be  attracted 


FIG.  244o. — THE  LUGO  MOTOR. 

to  f2  and  cause  rotation  in  the  direction  of  the 
hands  of  a  watch.  This  attraction  continues 
until  the  pole  pieces  M2,  f2,  have  arrived  ex- 
actly opposite  each  other,  or  in  the  position  in 
which  M1,  F1  is  shown.  At  this  instant,  how- 
ever, the  current  is  shifted  to  the  bobbins  M3, 
f3,  which  will  then  have  arrived  at  the  relative 


position  formerly  existing  between  M2  andF2, 
and  the  magnets  act  in  succession  as  follows  : 

M1,  F*;   M2,  F*;   M3,  F1: 

M3,  7^4;    M*,  F*,   and   back   to   the   starting 
point  M1,  F1. 

Thus,  in  every  revolution  of  the  armature 
shaft  each  armature  coil  is  placed  in  circuit 
with  each  field  coil ;  and,  there  being  four  of 
one  and  five  of  the  other,  it  follows  that  there 
are  twenty  successive  pulls  at  as  many  radial 
positions  of  the  shaft,  each  pair  of  coils  be- 
ing in  circuit  successively  only  during  one- 
twentieth  of  a  revolution  of  the  shaft.  It  will 
be  noticed  that  the  stationary  commutator  is 
divided  into  four  groups  of  segments,  five  in 


FIG.  244E. — THE  LUGO  MOTOR. 

each  group,  while  the  rotating  commutator  is 
divided  into  five  groups,  each  of  which  has 
four  segments.  An  examination  of  the  circuit 
diagram,  Fig.  244F,  will  show  the  commutation 
of  the  four  armatures  and  five  field  bobbins. 
It  is  evident,  however,  that  any  desired  num- 
ber of  field  and  armature  bobbins  may  be  com- 
bined, it  being  only  necessary  to  so  commutate 
the  circuits  as  to  make  the  effect  of  the  mag- 
netic pull  on  the  bobbins  successive  in  its  action. 
With  a  motor  constructed  in  the  manner  just 
described,  Dr.  Lugo  claims  to  utili/e  the  power 
due  to  the  attraction  of  the  pole  pieces  of  the 
armature  and  field  magnet  bobbins,  as  well  as 
that  due  to  the  parallelism  of  the  windings 
of  the  bobbins  as  they  approach  each  other 
during  the  rotation  of  the  armature,  thus  ob- 


238 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


fcaining  an  increased  effect  from  those  magnetic 
lines  of  force  which  are  ordinarily  radiated  to 
create  reverse  inductive  effects  detrimental  to 
the  efficiency  of  the  machine. 

The  arrangement  is  also  claimed  to  avoid  the 
evil  effects  due  to  self-induction,  for  the  reason 


FIG.  244F. — THE  LUGO  MOTOR. 

that  only  a  minimum  amount  of  effective  wire 
is  in  circuit  at  any  time,  and  that,  only,  at  the 
time  when  it  is  needed  to  give  the  best  effects. 
By  creating  the  effective  field  and  armature 
circuits  at  stated  intervals  and  only  when 
needed,  and  permitting  all  of  the  field  or  arma- 
ture bobbins  to  rest  or  be-  magnetically  or 


FIG.  245. — PATTEN'S  ELECTRIC  MOTOR. 

electrically  discharged  at  different  portions  of 
the  armature  rotation,  heating  and  waste  of 
energy  is  said  to  be  prevented.  The  Foucault 
currents  are  also  reduced  to  a  mimimum  by 
reducing  the  effective  field  and  armature  cir- 


cuits with  their  magnetic  cores  to  a  minimum, 
while  obtaining  their  maximum  effect.  The 
sparking  at  the  brushes  is  likewise  avoided  by 
reason  of  the  fact  that  there  is  no  magnetic 
lead  in  the  field  or  armature,  inasmuch  as  the 
field  travels  around  just  in  advance  of  the 
armature  as  each  bobbin  is  cut  in. 

.Among  other  novelties  which  the  machine  is 
claimed  to  possess  by  the  inventor  is,  that  both 
field  and  armature  circuits  are  conjointly  cut 
out  at  different  points  in  the  rotation  of  the 
armature,  thereby  utilizing  only  that  portion 
of  the  combined  circuit  which  is  needed  to  pro- 
pel the  motor  or  create  a  current  in  the  ma- 
chine when  used  as  a  dynamo.  The  efficiency 
of  this  motor  is  said  to  be  very  high,  and  the 
machine  is  very  light  and  simple  in  construc- 
tion. 


FIG.  240. — PATTEN'S  ELECTRIC  MOTOR. 

Lieut.  F.  Jarvis  Patten,  U.  S.  A.,  has  recently 
constructed  a  motor  of  the  novel  design  shown 
in  Figs.  245,  246  and  247.  Its  novel  features 
consist  mainly  in  a  new  system  of  armature 
winding,  commutators  and  connections,  as  well 
as  some  mechanical  details  worth}'  of  notice. 
In  the  accompanying  engravings,  Figs.  245  and 
246,  are  side  and  end  elevations  of  the  motor, 
half  of  each  being  shown  in  section. 

A  noticeable  feature  of  the  machine  is  an  ex- 
ceedingly short  magnetic  circuit  and  a  slightly 
unsymmetrical  field,  the  purpose  of  which  will 
be  explained  later.  The  motor  has  a  compara- 
tively large  proportion  of  iron,  a  single  magnet 
core  and  coil  forming  the  yoke  of  a  very  short 
and  stout  electro-magnet,  thus  bringing  the 
centre  of  gravity  of  the  entire  machine  to  the 
lowest  possible  point.  To  the  core  there  is 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


239 


bolted  by  a  single  transverse  bolt  the  two 
curved  pole-pieces  of  cast-iron,  which  are  so 
shaped  as  to  reduce  the  magnetic  lines  of  force 
to  their  shortest  length,  while  the  armature  iits 
so  closely  that  there  is  but  ^  of  an  inch  of  air 
space  in  the  magnetic  circuit. 

Secured  to  the  spindle  is  a  three-coil  arma- 
ture of  peculiar  construction.  The  coils  are 
wound  longitudinally  around  three  poles,  radi- 
ating at  angles  of  120  degrees  from'  the  spindle. 
The  armature  may  therefore  be  regarded  as  a 


FIG.  247. — PATTEN'S  ELECTRIC  MOTOR. 

drum  armature,  with  three  coils  and  a  mini- 
mum amount  of  inactive  wire  ;  the  ends  being- 
shortened  in  the  proportion  that  the  length  of 
a  chord  of  120  degrees,  or  less,  is  to  that  of  a 
diameter  of  the  same  circle.  These  three  coils 
of  the  armature  are  all  continually  in  circuit  in 
parallel  arc,  so  that  the  armature  consists  of  a 
three-coil  multiple-arc  winding,  thus  reducing 
materially  the  armature  resistance,  as  by  the 
peculiar  arrangement  of  the  field  described 


none  of  the  coils  of  the  armature  are  at  any 
time  cut  out  of  circuit. 

This  system  of  construction  admits  further 
of  a  non-sparking  commutator  for  all  positions 
of  the  brushes,  and  is  the  result  of  the  pecu- 
liar commutator  connections  rendered  neces- 
sary. These  are  shown  in  Fig.  247. 

As  will  be  seen,  there,  are  practically  two 
commutators,  one  revolving  under  the  posi- 
tive and  the  other  under  the  negative  brush, 
and  the  two  brushes  are  placed  upon  the 
same  side  of  the  spindle  and  at  opposite 
ends  of  the  armature.  This  arrangement,  it 
will  be  noticed,  leaves  the  entire  commutator 
exposed,  so  that  it  can  easily  be  cleaned  while 
the  machine  is  running.  In  Fig.  247  the  verti- 
cal lines  E  E,  represent  a  vertical  diameter  of 
the  armature  spindle,  and  each  segment  of  the 
commutator  is  shown  in  its  proper  relative  po- 
sition thereto.  An  examination  of  the  diagram 
of  connections  will  show  that  each  of  the  three 
coils  is  constantly  in  circuit,  and  is  entirely  in- 
dependent of  the  other  two.  The  action  of  a 
single  coil  during  one  revolution  will  therefore 
describe  that  of  all.  Tims,  in  Fig.  247,  the 
coil  A  is  shown  with  its  terminals  connected  to 
two  partial  commutators,  one  revolving  under 
the  positive,  and  the  other  under  the  negative 
brush.  The  coil  is  secured  by  one  terminal  to 
the  segment  a1  -f  ,  and  after  traversing  the  ar- 
mature has  its  other  end  secured  to  the  segment 
a1 — ,  which  revolves  under  the  negative  brush 
and  occupies  exactly  the  same  angular  position 
on  the  spindle  as  the  first  segment.  This  last 
segment,  however,  is  also  connected  by  a  free 
conductor  rlrl  back  to  the  second  segment 
a2  +  oi'  the  first  half  commutator ;  and  the -seg- 
ment a2 —  of  the  second  half  is  likewise  con- 
nected by  the  free  conductor  rsr2  back  to  the 
short  segment  a1  +  of  the  first  half. 

The  other  coils  of  the  armature  are  similarly 
connected  to  their  corresponding  commutator 
segments,  the  only  difference  being  that  the 
corresponding  segments  for  the  different  coils 
are  placed  in  rotation  around  the  spindle,  so 
that  their  middle  lines  make  with  each  other 
angles  of  just  120  degrees. 

If  now  the  current  be  regarded  as  flowing 
direct  from  the  positive  to  the  negative  brush, 
and  the  result  during  a  single  complete  revoiu- 


240 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


tion  of  the  coil  A  be  traced,  it  will  be  seen  that 
while  the  short  segments  a1  +  and  a1  —  are 
under  their  respective  brushes,  the  current  will 
flow  direct  in  the  coil  A  i'rom  the  positive  to 
the  negative  brush.  When,  however,  the 
short  segments  pass  out  of  action  the  current 
will  flow  from  the  positive  brush  B  +  ,  through 
the  long  segment  a2  -|-  ,  the  free  conductor  r1, 
over  to  the  short  segment  a1 —  (no  longer  un- 
der the  negative  brush),  then  back  through 
coil  A  in  a  reverse  direction  to  the  short  seg- 
ment a1  +  (no  longer  in  contact  with  the  pos- 
itive brush),  and  thence  through  the  free  con- 
ductor rsr2  to  the  long  segment  «2 — ,  and  out 
through  the  negative  brush  as  before. 

It  is  therefore  plain  that  the  current  flows 
direct  in  any  coil  while  the  short  segments  are 
under  the  brushes,  and  in  a  reverse  direction 
whenever  the  long  segments  are  in  contact 
with  the  brushes ;  and  this  change  takes  place 
alike  for  each  of  the  armature  coils  in  rotation. 

The  relative  amount  of  direct  and  reverse 
current  taken  in  a  revolution  by  each  coil  will 
depend  upon  the  relative  amount  of  the  spindle 
circumference  covered  by  the  long  and  short 
segments,  and  this  must  necessarily  depend 
upon  the  amount  of  distortion  or  unsymmet- 
rical  arrangement  of  the  field,  which,  for  well- 
known  reasons,  must  have  comparatively  nar- 
row limits.  This  distortion  of  the  field  amounts 
practically  to  changing  the  diameter  of  com- 
mutation from  a  right  line  (diameter)  to  a 
broken  line,  consisting  of  two  radii  meeting  in 
the  centre  of  the  spindle,  an  effect  involving, 
it  is  claimed,  no  disadvantages  under  the 
conditions  as  secured  and  provided  for,  viz., 
that  both  brushes  are  on  the  same  side  of  the 
spindle. 

If,  now,  the  further  condition  be  borne  in 
mind  that  the  coils  must  of  necessity  radiate 
at  equal  angles  of  120  degrees  from  the  spindle, 
and  we  give  to  the  field  poles  a  relative  posi- 
tion, as  shown,  such  that  the  points  on  the 
armature  circumference  where  the  current  must 
change  direction  are  at  the  extremity  of  radii 
that  are  inclined  at  some  angle  between  140  and 
160  degrees,  it  will  result  in  giving  to  the  ar- 
mature a  continuous  unbroken  circuit,  and  as 
the  three  coils  are  always  in  parallel  arc,  there 
can  be  no  short-circuiting  of  the  coils  due  to 


the  brush  bearing  upon  two  different  segments 
simultaneously. 

This  effect  is  shown  by  the  lower  diagram  in 
Fig.  247,  in  which  the  short  segments  are  shown 
as  covering  arcs  of  160  degrees  eacli  of  the  spin- 
dle circumference.  Any  two  successive  ones 
must,  therefore,  overlap  by  an  angle  of  20  de- 
grees, from  which  it  results  that,  there  is  no 
point  during  a  complete  revolution  at  which 
the  armature  circuit  is  broken.  F.r,  as  the 
current  changes  from  any  one  coil  at  any  point, 
there  are  two  others  in  contact  with  the  same 
brushes  that  form  a  continuous  circuit.  The 
resultant  effect  amounts  practically  to  mak- 
ing a  set  of  commutator  segments  that  cover 
3x160=480  degrees,  each  single  part  overlap- 
ping the  other  by  an  amount  equal  to  |  (160 — 
120)=20  degrees. 

Another  result  of  this  peculiar  form  of  ar- 
mature construction  is  the  complete  elimination 
of  a  dead  centre,  there  being  at  all  points  of  a 
single  revolution  a  continuous  rotary  torque, 
which  may  be  expressed  as  the  resultant  effect 
of  three  separate  tangential  efforts  which  can 
never  be  so  placed  as  to  neutralize  each  other. 

The  demand  for  motors  on  arc  light  circuits 
or  for  constant  current  has  led  Mr.  Wm.  Hoch- 
hausen,  the  electrician  of  the  Excelsior  Electric 
Company,  to  design  a  machine,  which,  with 
fixed  brushes,  should  regulate  so  as  to  keep 
constant  speed  with  a  variable  load,  and  with- 
out the  interposition  of  external  resistance. 
The  motor,  which  is  illustrated  in  the  accom- 
panying engraving,  Fig.  248,  has  a  single  mag- 
netic circuit  in  which  the  armature  is  included. 
The  latter  is  mounted  on  bearings  at  the  top  of 
two  arms  which  rise  from  the  base,  which  also 
constitute  the  bearing  of  the  electro-magnets, 
which  have  wrought-iron  cores  and  cast-iron 
pole  pieces. 

The  regulation  of  the  motor  is  effected  by 
varying  the  intensity  of  the  magnetic  field  to 
correspond  with  the  load.  For  this  purpose 
the  two  field-coils  are  divided  into  ten  sections, 
the  ends  of  which  are  brought  to  consecutive 
strips,  shown  at  the  side  of  and  below  the  ar- 
mature. 

The  governor  is  of  the  centrifugal  type,  and 
is  held  in  an  extension  bearing  at  one  end  of 
the  armature  shaft.  The  governor  acts  upon 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


241 


an  arm  which  extends  downwardly  and  oper- 
ates upon  a  contact-maker  which  touches  the 
various  contact  strips  to  which  the  field-coils 
are  connected.  Thus,  when  the  motor,  which 
is  series  wound,  runs  with  full  load  and  at  nor- 
mal speed,  all  the  sections  of  the  field-coils  are 
in  action  ;  as  the  load  diminishes  the  governor 
expands  from  the  momentarily  increased  speed 
and  cuts  out  successive  coils  in  the  fields.  This 
reduces  the  magnetic  strength  of  the  latter,  and 
brings  the  motor  back  to  the  same  speed  as 
before.  Conversely,  when  the  load  is  increased, 
the  speed  is  reduced  for  an  instant,  the  gov- 


When  the  motor  runs  without  load,  all  the  field- 
coils  are  cutout,so  that  the  resistance  is  that  of 
the  armature  alone,  or  1  ohm.  In  that  case  the 
energy  absorbed  by  the  motor  is  100  watts,  or 
a  little  over  -j-horse  power. 

Mr.  Hochhausen  has  also  designed  a  motor 
of    somewhat  similar  appearance,   but  neces 
sarily  different  in  details  of  construction,  for 
incandescent  circuits. 

At  the  American  Institute  Electrical  Exhi- 
bition last  year,  Mr.  W.  E.  Hyer,  of  Newburgh, 
N.  Y.,  exhibited  a  small  motor  designed  by 
him,  and  embodying  several  novel  features. 


FIG.  248. — NEW  HOCHHAUSEN  MOTOR. 


ernor  contracts  and  puts  additional  field  coils 
in  circuit  to  correspond  to  the  increased  speed. 
The  machine  illustrated  is  designed  for  3- 
horse  power  and  runs  at  2,000  revolutions  per 
minute,  taking  a  10-ampere  current,  such  as  is 
largely  employed  in  arc  lighting.  Its  weight 
is  250  pounds.  The  resistance  of  the  armature 
is  1  ohm,  and  that  of  the  full  field  also  1  ohm. 
Hence,  the  energy  lost  in  the  motor  when  run- 
ning at  full  speed,  with  10  amperes,  is  200  watts, 
and,  as  the  motor  delivers  8-horse  power  or  2,238 
watts,  its  efficiency  is  thus  about  90  per  cent. 


The  illustrations,  Figs.  249  and  250,  show  a 
sectional  and  perspective  view  of  it.  As  will 
be  noticed,  the  armature  is  placed  directly 
within  the  helices  of  the  field-coils,  which  are 
wound  on  spools  of  non-magnetic  material. 
Both  field  coils  and  armature  are  surrounded 
by  an  iron  shell,  cast  in  two  parts,  and  having 
the  bearings  extending  horizontally  across  the 
open  ends.  This  construction  serves  to  close 
the  magnetic  circuit,  and  so  completely  is  this 
accomplished  that  no  external  magnetism  can 
be  detected.  By  means  of  this  construction, 


242 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


it  is  claimed,  very  high  efficiency  is  obtained, 
that  of  the  small  -£$  horse  power  motor  reaching 
65  per  cent.,  with  a  corresponding  increase  in 
the  larger  sizes. 

The  armature  of  this  motor  is  of  the  Gramme 
form,  and  its  core  is  built  up  of  rings  of  soft 


FIG.  24!). — THE  HYER  ELECTRIC  MOTOR. 

sheet-iron,  insulated  magnetically  from  each 
other,  and  thus  entirely  avoiding  eddy  currents. 
It  is  wound  in  sections  varying  in  number  ac- 
cording to  the  size  of  motor,  and  is  secured 
to  the  shaft  between  two  brass  discs.  One  of 


FIG.  250. — THE  HYER  ELECTRIC  MOTOR. 

these  fits  against  a  shoiilder  in  the  shaft,  and 
the  other  is  forced  against  the  winding  by 
means  of  a  nut  on  the  shaft.  The  commutator 
is  a  flat  one,  and  is  placed  against  the  end  of 
tne  armature,  and  the  brushes  are  secured  to 


lugs  cast  to  the  frame.  The  motor  illustrated 
is  of  a  rated  capacity  of  TVhorse  power,  but  it 
may  be  worked  up  to  ^-horse  power  without,  in- 
j  ury.  It'  occupies  a  space  of  4  x  4  inches,  is  5 
inches  high  and  weighs  6£  Ibs.  The  motor  of 
£-horse  power  is  7x6  inches  by  7  indies  high, 
and  weighs  30  Ibs.  The  motors,  with  the  ex- 
ception of  that  of  TVhorse  power,  are  compound 
wound,  and  show  good  regulation. 

The  illustration,  Fig.  251,  represents  an  elec- 
tric motor  recently  brought  out  by  the  Hawk- 
eye  Electric  Manufacturing  Company,  of  Oska- 
loosa,  la.,  and  designed  by  their  electrician, 
Mr.  Thone.  As  will  be  seen,  the  armature  is 


FIG.  251.—  THE  THONE  ELECTRIC  MOTOR. 

of  the  disc  type,  and  two  field-coils  are  em- 
ployed. The  machine  is  shunt  wound,  and 
designed  to  be  self-regulating,  without  neces- 
sitating the  shifting  of  the  brushes  or  the  em- 
ployment of  rheostats.  A  switch  is  attached 
to  the  motor,  by  which  it  is  thrown  into 
circuit  gradually,  thus  preventing  an  abnormal 
flow  of  current  at  starting.  These  machines 
are  built  in  sizes  ranging  from  £  to  10- 
horse  power.  Those  up  to  4-horse  power  are 
adapted  to  circuits  ranging  from  50  to  110 
volts,  and  the  larger  sizes  from  110  to  220  volts. 
Figs.  252,  253  and  254  illustrate  two  types  of 
motors  designed  by  Mr.  Geo,  F.  Card,  and 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


243 


recently  brought  out  by  the  Gr.  F.  Card  Manu- 
facturing Company,  of  Cincinnati,  0.  These 
machines  are  of  the  bi-polar  type  with  Gramme 
ring  armatures. 


FIG.  252. 
THE  CARD  CONSTANT-POTENTIAL  MOTOR. 

The  constant-potential  motor,  type  "B," 
shown  in  the  engraving,  Fig.  252,  is  wound  for 
a  current  of  2£  amperes,  the  field  and  armature 
being  in  series.  With  a  current  of  ]£  amperes, 
the  motor  attains  a  speed  of  5,000  revolutions 
per  minute.  It  measures  6x7£  inches,  stands 
5  inches  high  and  weighs  9  Ibs.,  without  the 
base.  A  resistance-box  of  lamps,  of  lower  vol- 
tage than  the  dynamo,  arranged  in  parallel,  is 
used  on  the  incandescent  circuit.  By  turning 
them  out  singly,  and  increasing  the  resistance, 
the  speed  of  the  motor  can  be  reduced  at  will. 
By  the  use  of  a  larger  number  oi  lamps,  of  the 
same  voltage  as  the  dynamo,  a  corresponding 
increase  in  the  number  of  variations  in  the 
speed  can  be  effected.  The  current  can  te 
thrown  off  from  the  motor  entirely,  without 
disturbing  the  lamps,  arid  then  their  light,  be- 


ing nearly  up  to  full  candle-power,  can  be  util- 
ized by  a  reflector.  It  will  be  noticed  that,  in 
this  style  of  motor,  besides  the  usual  field 
magnets,  an  additional  branch  is  added,  which 
arches  from  pole  to  pole  and  encircles  one  of 
the  bearings  of  the  shaft. 

The  constant-current  motor,  illustrated  in 
Fig.  253,  is  series  wound,  and  is  designed  for  a 
current  of  five  amperes  and  to  run  at  a  speed 
of  5,000  revolutions  per  minute.  In  order  to 
be  able  to  operate  the  motor  on  a  10-ampere 
circuit,  a  shunt  resistance  of  carbon  is  em- 
ployed, by  means  of  which  five  different  speeds 
can  be  obtained. 


FIG.  253. — THE  CARD  CONSTANT-CURRENT  MOTOR. 

One  of  the  features  of  the  Card  motors  is 
the  reversible  commutator,  shown  at  the  side 
of  the  armature  in  Fig.  254.  This  is  so  arranged 
that  all  the  sections  can  be  removed  and  re- 
placed without  disturbing  a  wire.  If  worn  on 


244 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


one  face  the  sections  can  be  reversed ;  or  if  worn 
on  both  faces,  so  as  to  be  serviceable  no  longer, 
new  ones  can  be  inserted.  The  inventor,  after 
an  experience  of  nearly  a  year  with  a  dynamo 


FIG.  254. — ARMATURE  OF  CARD  MOTOR. 

of  considerable  size,  in  which  this  form  of  com- 
mutator is  used,  claims  that  the  uneven  wear 
on  the  brushes,  which  might  be  supposed  to 
interfere  with  the  practical  workings  of  the 
device,  is  an  entirely  negligible  quantity.  This 
arrangement  of  the  brushes  also  admits  of  an 


PIG.  255. 
DIEHL  COMBINED  SEWING-MACHINE  AND  MOTOR. 

observation  being  taken  on  both  at  the  same 
time,  and  is  convenient  in  setting  the  brushes. 
There  is  to  day  probably  no  domestic  labor- 
saving  device  in  more  general  use  than  the 
sewing-machine,  and  it  ranks  rightly  as  one  of 
the  prominent  inventions  of  this  century. 
While,  however,  it  saves  a  vast  amount  of 


manual  labor,  its  continuous  use  for  hours,  en- 
tailing the  employment  of  a  treadle,  has  called 
for  methods  of  driving  the  machines  by  auxil- 
iary power  ;  and  in  large  factories  they  are  fre- 
quently coupled  to  lines  of  shafting.  This 
method  of  driving  has  not  been  applicable  to 
the  case  of  isolated  machines,  whether  in  shops 
or  private  dwellings,  and  hence  the  advent  of 


Fio.  256. — FIELD  MAGNET  OF  DIEHL  MOTOR. 

the  electric  motor,  which  permitted  each  ma- 
chine to  be  independent  of  any  other,  was 
welcomed,  because  it  offered  a  ready  means  of 
accomplishing  in  a  convenient  manner  what 
was  heretofore  impracticable.  The  small  mo- 


FIG.  257. — DETAIL  OF  ARMATURE  WINDING. 

tors  have,  as  a  rule,  been  attached  to  the  board 
on  which  the  sewing-machine  is  mounted,  and 
then  belted  to  the  shaft  of  the  latter. 


LATEST  AMERICAN  MOTORS  AND  MOTOR  SYSTEMS. 


245 


It  was  to  avoid  the  necessity  of  belting,  and 
at  the  same  time  do  away  with  the  presence  of 
an  auxiliary  machine  on  the  board  for  driving, 
that  Mr.  Philip  Diehl,.of  Elizabeth,  N.  J.,  one 
of  whose  ingenious  motors  has  already  been 
described,  conceived  the  idea  of  combining 
the  motor  and  sewing-machine  into  a  prac- 
tical unit. 

The  simple  and  elegant  manner  in  which  he 
has  accomplished  this  is  shown  in  the  engrav- 
ing, Fig.  255.  The  motor,  it  will  be  seen,  is 
completely  housed  within  the  fly-wheel  of  the 
machine,  and  connected  directly  with  the  driv- 
ing-shaft, so  that  all  gearing  is  obviated.  The 
details  of  the  arrangement  will  be  readily  un- 
derstood from  Figs.  256  and  257,  which  show 
respectively  the  field  magnet  and  armature  of 
the  motor.  The  magnet,  which  consists  of  a 
single  piece,  is  wound  with  wire  connected  to 
the  two  terminal  brushes  shown.  This  magnet 
is  permanently  fixed  to  the  hub  through  which 
the  shaft  passes.  The  armature  shown  in  per- 
spective in  Fig.  257  is  of  the  Gramme  type, 
and  is  held  in  position  within  the  rim  of  the 


wheel.  The  wires  leading  from  the  periphery 
connect  to  the  commutator  at  the  hub,  and  the 
brushes  on  the  magnets  bear  against  the  seg- 
ments. 

The  wires  leading  to  the  motor  pass  up 
through  the  hollow  casting  of  the  frame,  and 
are  connected  to  a  switch,  by  which  the  ma- 
chine can  be  started  and  stopped  at  will.  The 
fly-wheel  is  provided  with  a  clutch  or  stop  mo- 
tion in  connection  with  the  shaft,  so  that  it 
may  be  connected  with  the  latter,  or  turned 
loose,  as  is  common  in  sewing-machines — the 
wheel  being  disconnected  from  the  shaft  when 
winding  bobbins.  This  is  accomplished  by  a 
turn  of  a  thumb-nut  at  the  rear  end  of  the 
machine.  By  unscrewing  this  nut  entirely,  the 
armature  may  be  slid  out  completely,  so  that 
it  may  be  examined  should  necessity  require. 
This  also  exposes  the  field  magnets  and  brushes, 
so  that  they  can  be  easily  gotten  at  for  exam- 
ination and  attention.  The  entire  motor  is  put 
together  in  a  most  compact  and  neat  form,  and 
it  adds  greatly  to  the  value  of  the  sewing- 
machine  as  a  labor-saving  device. 


CHAPTER   XIV. 
LATEST  EUROPEAN  VIOTORS  AND  XIOTOR  SYSTEMS — CONTINUED. 


NOTWITHSTANDING  the  variety  of  methods 
and  devices  employed  in  transmitting  the  cur- 
rent from  the  central  station  to  the  motor  on 
the  car,  to  which  attention  has  already  been 
called,  there  are  still  new  ones  to  make  their 
appearance,  and  some  of  them  must  be  credited 


Mr.  Pollak  uses  the  rails  as  the  first  conduc- 
tor, but  the  second  conductor  is  completely  in- 
sulated under  the  road,  and  does  not  commu- 
nicate directly  witli  the  exterior.  The  current 
enters  the  car  by  means  of  a  third  rail  place.l 
in  the  middle  of  the  track.  Fig.  258  shows 


FIG.  258. — POLLAK  AND  BINSWANGER'S  ELECTRIC  J{AILWAY. 


directly  to  European  ingenuity.  Among  the 
most  recent  of  these  is  the  system  of  Messrs. 
Pollak  and  Binswanger,  the  chief  point  of 
novelty  of  which  consists  in  the  ingenous 
method  adopted  for  transferring  the  current 
from  an  insulated  conductor  to  the  motor  on 
the  car. 


this  .arrangement  in  longitudinal  section,  and 
Fig.  2H9  in  transverse  section.  This  rail, 
which  should  be  made  of  soft  iron,  is  divided 
into  segments  of  about  3  to  4  metres  in  length, 
insulated  from  each  other  electrically  by  means 
of  wocd  and  fibre.  Each  segment  is  formed 
of  two  parallel  bands  of  iron,  li,  separated  by 


LATEST  EUROPEAN  MOTORS  AND  MOTOR  SYSTEMS. 


247 


a  non-magnetic  body,  such  as  wood,  as  shown 
in  Figs.  260  and  261. 

Ordinarily  these  segments  do  not  communi- 
cate with  the  insulated  conductor  ;  each  of  them 
is  fitted  with  two  metallic  boxes  K,  Fig.  261, 


FlG.  259. — POLLAK  AND  BlNSWANGER'S 

ELECTRIC  RAILWAY. 

firmly  fixed  below,  and  into  whicli  penetrate 
the  branches  of  the  principal  conductor.  These 
branches  abut  on  pieces  of  soft  iron  n,  termi- 


rail.  These  then  attract  the  piece  of  iron  TO, 
which  closes  a  contact,  bringing  the  segments 
into  communication  with  the  principal  conduc- 
tor. Consequently,  at  this  moment  the  brushes 
resting  on  the  central  rail  can  collect  the  cur- 
rent. When  the  car  has  passed,  the  segments 
are  demagnetized,  the  iron  contacts  fall  back, 
and  the  communication  between  the  segment 
and  the  principal  conductor  is  broken. 

The  boxes  K,  in  which  these  contacts  are 
made,  are  closed  hermetically  and  half  filled 


FIG.  261. 

witli  petroleum,  which  prevents  moisture  from 
gathering  on  the  different  parts. 

The  insulation  of  the  boxes  may  be  rendered 
practically  perfect,  so  that  losses  from  faulty 
insulation  can  take  place  only  between  the  cen- 
tral segment  placed  beneath  the  car  and  the 
extreme  rails  on  the  surface  of  the  earth.  The 
loss,  being  limited  to  so  trifling  a  length,  is 
insignificant.  The  cost  of  laying  the  line  is  not 
high  in  comparison  with  the  systems  having 
underground  channels ;  the  central  conductor 


FIG.  260. — POLLAK  AND  BINSWANGER'S  ELECTRIC  RAILWAY. 


nated  by  a  piece  TO,  also  of  iron,  jointed  to  the 
former,  and  connected  with  it  besides  by  the 
spring  r. 

The  car  is  fitted  with  a  powerful  magnet, 
NS,  Figs.  258  and  259,  the  poles  of  which  mag- 
netize, by  induction,  the  two  segments  of  the 


being  well  insulated,  there  is  no  occasion  to 
make  a  drain  or  to  interfere  with  the  road.  The 
chances  of  deterioration  are  claimed  to  be  very 
slight,  as  no  delicate  part  is  exposed.  The  car 
always  covers  the  segments  which  communicate 
with  the  underground  conductor,  so  that  there 


248 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


is  neither  danger  of  short-circuiting  nor  of  giv- 
ing shocks  to  men  or  horses  traversing  the  road. 
The  system  permits  of  the  use  of  high  poten- 
tials, and  consequently  effects  a  great  reduction 
in  the  loss  in  the  conductors.  In  fact,  with  a 
difference  of  potential  of  500  volts,  6  amperes 
suffice  to  furnish  four  electrical  horse-power, 
which  is  enough  for  propelling  a  small  car 
under  ordinary  conditions. 


FIG.  262. — THE  IMMISCH  MOTOR. 

The  different  figures  accompanying  the  text 
refer  to  the  reduced  model  of  this  tramway  as 
it  has  been  presented  to  and  worked  before  the 
Paris  International  Society  of  Electricians. 

Instead  of  bringing  the  current  by  the  central 
rail,  and  letting  it  return  by  the  two  others,  it 
will  often  be  advantageous  to  make  use  only  of 
two  rails  properly  so-called.  One  of  them  is  di- 
vided into  segments,  like  the  central  rail  just  de- 
scribed while  the  other  remains  as  it  was.  In  this 
case  the  wheels  placed  on  one  side  of  the  car 
have  to  be  insulated  from  their  axles.  The 
central  rail  is  especially  advantageous  when  it 
is  required  to  convert  a  line  already  existing. 

In  order  to  employ  gear-wheels  the  inventor 
makes  use  of  slow  speed  motors  which  revolve 
only  about  500  times  per  minute,  so  that  a 
single  transmission  by  a  cog-wheel  is  sufficient 
to  transmit  the  rotation  from  the  dynamo  to 
the  wheels  of  the  car,  which  at  their  normal 
speed  make  from  100  to  120  turns  per  minute 
(16  kilometres  per  hour,  with  wheels  of  a  dia- 
meter of  .8  metre).  The  illustration,  Fig.  258, 
made  from  a  model,  however,  shows  a  worm 
gear  employed  as  the  means  of  transmission. 

Considerable  attention  has  lately  been  drawn 
in  England  to  the  Immisch  motor,  which  em- 
bodies some  novel  features,  especially  in  the 


winding  of  the  armature.  The  machine  of  6 
horse  power,  is  shown  in  perspective  in  Fig.  262 
and  the  manner  of  winding  the  armature  is 
shown  diagramatically  in  Fig.  263.  In  the  dia- 
gram only  eight  coils  are  indicated,  although 
48,  96  or  more  may  be  employed.  The  commu- 
tator is  of  the  bisected  type,  and  the  coils  are 
joined  to  two  adjacent  segments  of  the  com- 
mutator on  the  two  rings,  of  which  one  lias  an 
angular  advance  equal  to  one-half  the  width  of 
the  commutator  bar.  The  two  brushes  side  by 
side  upon  the  two  rings,  are  connected  together 
so  that  only  one  pair  is  shown  in  the  figure. 

Starting  from  one  ring  of  the  commutator 
under  the  brush,  say,  with  the  coil  marked  1, 
it  crosses  to  the  other  side  of  the  armature  and 
joins  the  connection  leading  to  coil  6 ;  but  if 
we  follow  this  line  backward  to  the  commuta- 
tor, we  arrive  at  a  segment  under  the  same 
brush  from  which  we  started.  Similarly  coil  5 
connects  with  coil  2,  and  is  short-circuited  in 
the  same  way  by  the  other  brush.  It  will  be 
observed  that  the  magnetic  axis  of  the  armature 
itself  would  be  situated  underneath  the  coils 
which  are  short-circuited.  The  remaining  con- 
nections are  easy  to  follow  ;  the  two  halves  of 


FIG.  263. — THE  IMMISCH  MOTOR. 

the  circuit  can  be  traced  through  coils  6,  3  and 
4  in  series  on  the  one  side,  and  coils  8,  7  and  2  in 
series  on  the  other.  It  is  to  be  observed,  how- 
ever, that  this  arrangement  only  amounts  to  the 
same  as  having  an  armature  of  normal  type 
with  a  brush  of  wide  face,  so  that  its  contact 


LATEST  EUROPEAN  MOTORS  AND  MOTOR  SYSTEMS. 


249 


with  two  adjacent  commutator  bars  is  consider- 
ably prolonged. 

It  was  thought  probable  when  the  first  ex- 
periments were  made,  that  difficulties  might  be 
experienced  from  the  heating  of  the  coils  dur- 


FIGS.  264  and  265.— RIVETING-MACHINE. 

ing  the  period  of  short  circuiting,  which  occurs 
twice  in  every  revolution.  No  such  effect  has 
practically  been  found  to  occur  so  long  as  the 
field  poles  are  properly  proportioned,  and,  in 
the  case  of  a  motor,  the  brushes  may  even  be 
shifted  some  distance  to  either  side  of  the  nor- 
mal position,  without  producing  either  spark- 
ing or  any  increase  of  heating.  But  curiously 
enough  this  does  not  apply  to  a  dynamo  of 
similar  construction,  the  position  of  the  brushes 
having  to  be  adjusted  with  some  care.  So  long 
as  this  is  attended  to,  the  machine  runs  with 
perfect  smoothness,  but  as  soon  as  the  brushes 
are  displaced,  although  no  sparking  takes 
place,  yet  considerable  and  rapid  heating  is 
the  result.  It  is  claimed,  however,  that  this 
is  of  little  practical  importance,  for  when  the 
position  of  the  brushes  has  been  once  deter- 
mined, they  can  be  rigidly  fixed.  It  is  said 
that  the  non-heating  of  the  coils  proves  that 
during  this  part  of  the  revolution  the  algebra- 


ical sum  of  the  number  lines  of  force  passing 
through  it  is  constant. 

The  average  efficiency  of  one  of  these  motors 
run  at  between  1,400  and  2, 200  re  volutions,  and 
delivering  from  .98  to  1.76  horse  power,  was  71 
per  cent.  In  a  larger  motor  of  from  4.5  to  5- 
horse  power,  85  per  cent,  efficiency  was  obtained. 

It  is  often  of  great  convenience  to  be  able  to 
use  certain  tools  in  places  whither  it  has  been 
difficult  to  comvey  energy.  Of  late  years  the 
use  of  hydraulic  machinery  has,  to  a  certain 
extent,  enabled  apparatus  to  be  used  in  such 
situations,  but  it  does  not  fully  supply  the  re- 
quirements. Attempts  have  been  made  to  use 
electricity  for  the  purpose,  and  one  of  the  most 
successful  of  these  is  to  be  found  in  the  appa- 
ratus designed  by  Mr.  Rowan,  of  Glasgow,  in- 
tended more  especially  for  ship  work ;  but,  of 
course,  the  apparatus  is  useful  for  many  other 
purposes. 

Fig.  264,  shows  a  small  riveter,  operated  by 
means  of  a  helical  cam,  shown  in  side  elevation 


FIG.  2G6. — DRILLING-MACHINE. 

at  Fig.  265,  which  works  in  the  line  of  the  ham- 
mer-rod, between  cross  heads  connected  by  four 
rods,  to  the  lower  of  which  cross-heads,  the 
hammer-rod  is  attached.  The  machine  has 


250 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


holding-on  magnets,  and  a  spiral  or  volute  cam, 
which,  through  an  anti-friction  roller  on  an 
arm,  lifts  the  hammer-rod  against  a  spiral  - 
spring,  which,  when  released  by  the  cam,  oper- 


£^.   WsrUi.  -V.  y 

FIG.  267. — CHIPPING-MACHINE. 

ates  to  produce  the  blow  of  the  hammer.  The 
spiral-spring  is  compressed  between  the  ham- 
mer-head and  a  disc  or  plate,  working  in  a 
circular  guide-box,  its  position,  and  consequent- 


FIG.  268. — CALKING-MACHINE. 

ly  the  amount  of  compression  given  to  the 
spring,  being  regulated  by  two  screwed  spindles 
working  through  the  top  of  the  guide-box,  and 
moved  by  gearing. 


The  illustration,  Fig.  266,  shows  an  arrange- 
ment of  an  electro-magnetic  drilling-machine  for 
a  single  drill  spindle,  capable  of  being  traversed 
horizontally  along  the  frame  to  which  the 
motor  is  attached.  It  represents  also,  a  cross- 
section  of  a  multiple  drilling-machine. 

Another  application  of  electricity  in  a  kin- 
dred way,  is  shown  in  Figs.  267,  268  and  269, 
which  represent  calking  and  chipping-ma- 
chines.  In  the  first  of  these  the  tool  is  shown, 
actuated  by  an  electric  motor  through  gearing, 
lifting-cam  and  spring,  as  in  the  riveting-ma- 
chine. The  other  illustrations,  Fig.  268  and 
269,  show  in  section  and  elevation,  an  arrange- 
ment of  solenoid  coils  for  producing  a  recipro- 
cating motion  so  as  to  deliver  blows.  The  tool 
is  supported  by  a  holding-on  magnet,  to  which 
it  is  attached  by  an  arm  and  traversing  screw 


FIG.  269. — ELECTRIC  CALKING-MACHINE. 

and  a  ball  and  socket,  or  swivel-pin  joint,  which 
allow  its  position  and  angle  to  alternate  at  will. 
A  noteworthy  instance  of  the  successful  trans- 
mission of  power  by  means  of  electric  motors, 
has  been  afforded  by  some  work  recently  per- 
formed in  Switzerland,  by  the  Oerlikon  ma- 
chines, designed  and  built  by  Mr.  C.  E.  L. 
Brown,  of  Zurich.  Fig.  270  is  an  engraving  of 
the  Oerlikon  machine,  and  Fig.  271  shows  the 
circuits  and  the  disposition  of  the  generators 
and  motors,  two  of  each  being  employed.  The 
generators  and  motors  are  similar  in  construc- 
tion, but  differ  in  some  of  their  proportions  and 
in  the  winding.  The  field  magnets  are  formed 
of  two  vertical  pillars  of  wrought-iron,  which 
are  united  above  and  below  by  cast-iron  pole 
pieces,  the  pillars  simply  fitting  into  borings 
in  the  latter.  The  lower  pole  piece  is  cast 


LATEST  EUROPEAN  MOTORS  AND  MOTOR  SYSTEMS. 


251 


in  one  piece  with  two  supports  i'or  the  armature. 
The  driving  pulley  (not  seen  in  the  out)  is  in- 
.side  the  armature  bearing.  The  dynamo  frame 
instead  of  being  bolted  to  the  floor,  fits  in  a 
slide-rest  on  a  firmly  secured  bed -plate,  and  by 
turning  a  hand-wheel  the  tension  of  the  belt 
may  be  varied  at  will  while  the  machine  is  in 
motion.  The  exciting  bobbins  of  the  field  mag- 
nets are  wound  separately  on  spools  which  slide 
easily  over  the  wrought-iron  cores.  The  whole 


Pigs.  272  and  273  represent  the  arrangement  for 
a  Gramme  ring,  and  it  will  be  noticed  that  the 
sections  of  the  windings  in  the  armature  imme- 
diately below  the  surf  ace  may  be  comparatively 
large,  thus  counteracting  their  comparatively 
confined  position  for  radiation,  and  making  it 
possible  that  the  same  number  of  conductors 
can  be  obtained  outside  and  inside.  It  is  ob- 
vious that  with  the  conductors  entirely  inside 
the  armature,  the  latter  can  be  run  exceedingly 


FIG.  270.— THE  BROWN   (OERLIKON)   MOTOR. 


construction  is  exceedingly  simple,  compact  and 
neat. 

The  principle  novelty,  however,  is  to  be  found 
in  the  peculiar  construction  of  the  armature. 
The  latter  is  a  modified  Pacinotti-Gramme  ring 
with  an  unusally  large  iron  section ;  but,  de- 
parting from  the  customary  method  of  placing 
the  windings  or  conductors  on  the  surface,  Mr- 
Brown  places  them  in  special  borings  imme- 
diately below  the  surface  of  the  armature. 


close  to  the  pole  pieces  ;  the  air-space  between 
armature  and  pole  pieces  is  reduced  to  a  mini- 
mum, and  the  conductors  move  through  a  most 
intense  magnetic  field. 

The  experiments  were  made  by  a  committee 
of  engineers  and  scientific  men,  with  a  view  of 
ascertaining  the  total  commercial  efficiency  of 
the  transmission  plant ;  but  as  the  machines 
were  in  this  case  placed  side  by  side,  the  re- 
sults could  only  be  taken  as  approximately 


252 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


correct.  It  is  evident  that,  in  such  an  arrange- 
ment of  machines  and  resistances  erected  within 
the  limits  of  a  covered  workshop,  the  insulation 
of  the  circuits  presents  no  difficulty  whatever, 
whereas  in  the  actual  installation,  when  many 
miles  of  overhead  wires  must  be  used,  the  insu- 
lation becomes  a  matter  of  some  difficulty,  and 
atmospheric  influences  may  also  have  some 
effect  upon  the  performance  of  the  plant. 
These  considerations  induced  the  makers  to 


of  October,  1887,  with  the  plant  as  actually 
installed.  Before  quoting  the  results  of  these 
trials,  it  will  be  well  to  briefly  refer  to  the  gen- 
eral arrangement  of  the  installation.  At  Krieg- 
stetten,  there  is  a  water-power  available,  rep- 
resenting about  forty  actual  horse  power,  and 
the  problem  was  to  carry  as  much  of  this  power 
as  possible  to  a  mill  in  Solothurn,  the  distance 
being  4J  miles  as  the  crow  flies  ;  but,  allowing 
for  deviations,  the  length  of  each  circuit  may 


KRIEGSTETTEN.  SOLOTHURN. 

FIG.  271. — TRANSMISSION  OF  POWER  BY  OERLIKON  MACHINKS. 


arrange  for  some  further  trials  with  the  plant 
as  actually  installed.  A  committee  was  ap- 
pointed, under  the  presidency  of  Professor 
Amsler,  of  Schaffhausen,  the  well-known  in- 
ventor of  the  planimeter,  and  other  well-known 
gentlemen  were  members,  among  them  Pro- 
fessor Weber,  of  the  Zurich  Polytechnic  School. 
This  committee  have  lately  issued  their  offirhil 
report  on  the  trials  made  on  the  llth  and  12th 


be  taken  as  about  five  miles.  There  are  at 
Kriegstetten  two  generating  dynamos,  and  at 
Solothurn  two  motors,  coupled  up  on  the'  thive- 
wire  system,  as  shown  in  the  illustration,  Fig. 
271.  Each  dynamo  weighs  3  tons  12  cwt.,  and 
has  a  Gramme  armature  20  in.  in  diameter  and 
14  in.  long,  the  normal  speed  being  700  revolu- 
tions per  minute.  Referring  to  the  diagram  of 
connections,  (?1  and  G2  are  the  generators  at 


LATEST  EUROPEAN  MOTORS  AND  MOTOR  SYSTEMS. 


Kriegstetten,  and  Ml  and  M2  are  the  motors 
at  Solothurn.  Jil  and  R2  are  electro-magnetic 
switches,  which  automatically  come  into  action 
and  short-circuit  the  exciting  coils  in  case  of 
the  current  rising  beyond  a  certain  limit.  This 
provision  was  introduced  in  order  to  guard 
against  the  destruction  of  the  generator  in  case 
a  short-circuit  should  take  place  somewhere  on 
the  line.  The  current  from  each  of  the  gener- 
ators passes  through  an  ammeter  and  then  to  a 
plug  switch-board,  P,  to  which  is  also  con- 
nected the  balancing  wire  joining  the  negative 
brush  of  (r2  with  the  positive  brush  of  G^ 
The  balancing  wire  is  then  carried  direct  to  the 
middle  one  of  the  three  lightning  arresters,  L, 
and  then  to  the  middle  wire  of  the  line,  while 
each  of  the  outside  wires  is  led  through  a  liquid 


FIGS.  272  AND  273.— THE  BROWN  DYNAMO. 

switch,  <S'j  £g,  then  to  a  lightning  arrester,  and 
to  the  line.  Each  lightning  arrester  consists  of 
a  circular  metal  disc,  the  edge  of  which  is  pro- 
vided with  projecting  teeth,  and  situated  in  a 
concentric  metal  ring,  the  internal  circum- 
ference of  which  is  also  provided  with  teeth, 
but  not  touching  the  teeth  of  the  disc.  All  the 
discs  are  connected  with  a  common  earth  wire 
and  two  earth  plates,  E  E.  The  same  pro- 
vision against  lightning  is  made  at  the  motor 
station.  The  switches  Sl  S2  are  of  peculiar 
construction,  and  consist  of  a  vessel  containing 
a  conducting  liquid  and  a  perforated  metal  ball 
dipping  into  it.  When  the  current  is  to  be 
switched  off,  the  handle  is  turned  so  as  to  raise 
the  ball  out  of  the  liquid  ;  but  the  circuit  is 
not  immediately  interrupted,  since  the  liquid 
within  the  balls  issues  in  fine  streams  out  of 
the  perforations,  and  so  maintains  the  connec- 
tion for  a  short  time  after  switching  off.  As 
the  liquid  in  the  ball  gets  exhausted,  and  the 
streams  become  thinner,  the  resistance  of  the 


liquid  connection  is  gradually  increased  to  in- 
finity, and  thus  causes  the  current  to  gradually 
diminish  to  zero.  The  line  wires  are  supported 
on  Johnson  &  Phillips'  patent  fiuid  insulators, 
and  the  average  span  is  about  130  ft. 

Two  sets  of  experiments  were  made.  On  the 
llth  of  October  only  one  generator  and  one 
motor  were  tested,  while  on  the  12th  of  October 
both  generators  and  both  motors  were  tested. 
In  the  latter  test  the  balancing  wire  was  cut  out 
of  circuit  as  of  no  importance,  when,  as  in  these 
experiments,  it  was  quite  easy  to  regulate  the 
load  of  each  motor  so  as  to  fairly  divide  the 
work  between  them. 

Electrical  measuring  instruments  were  fitted 
up  at  both  stations  in  rooms  sufficiently  distant 
from  the  machinery  so  as  not  to  be  influenced 
by  stray  magnetism.  The  current  was  meas- 
ured by  large  tangent  galvanometers,  and 
Thomson  mirror  galvanometers,  standard  cells, 
and  potentiometers  were  used  to  measure  the 
pressure.  The  object  in  measuring  the  current 
at  both  ends  of  the  line  was  to  ascertain  whether 
any  appreciable  leak  took  place.  In  addition 
to  these  purely  electrical  measurements,  obser- 
vations were  made  at  the  generator  station  re- 
garding the  water  level  in  the  head  and  tail  race 
of  the  turbine,  the  position  of  the  regulator  on 
the  latter,  and  the  speed  of  the  dynamos  and 
turbine.  After  the  transmission  trial  on  the 
llth  of  October  was  completed,  the  armature  of 
the  dynamo  was  taken  out  and  replaced  by  a 
plain  spindle,  provided  at  the  end  with  a  brake. 
The  turbine  was  then  started  again  under  ex- 
actly the  same  conditions  as  were  noted  at  the 
previous  trial,  and  the  power  absorbed  by  the 
brake  was  measured.  The  comparison  between 
the  power  thus  measured  and  the  electrical 
energy  given  out  by  the  generator  is  evidently 
the  commercial  efficiency  of  the  latter.  On  the 
following  day,  both  generators  and  both  motors 
were  tested  in  the  same  condition  as  prevails  in 
actual  practice,  with  the  only  exception  that, 
as  already  mentioned,  the  balancing  wire  was 
cut  out  of  circuit.  This  alteration,  which  could 
obviously  not  increase  the  efficiency  of  the 
whole  system,  was  made  to  simplify  the  meas- 
urements. The  power  absorbed  by  the  gener- 
ators was  computed  on  the  basis  of  the  previous 
day's  trial  from  the  observed  conditions  under 


254 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


which  the  turbine  worked,  while  the  power 
developed  by  the  motors  was  on  both  days 
directly  ascertained  by  means  of  a  friction 
brake  fitted  to  a  first  motion  shaft  common  to 
both  motors.  A  small  correction  was  made  for 
the  power  absorbed  by  this  shaft  when  ninning 
idle.  The  tables  subjoined  give  the  results  as 
published  by  the  committee. 

An  inspection  of  these  figures  will  show  that 
there  is  practically  no  loss  of  current  by  leak- 
age on  the  line.  In  some  cases  the  current 
measured  at  the  motor  station  is  slightly  below 
that  measured  at  the  generator  station  ;  but 
the  discrepancy  is  exceedingly  small,  and  evi- 
dently due  to  personal  or  instrument  errors, 


since  in  some  other  cases  the  current  received 
by  the  motors  appears  to  be  even  slightly 
larger  than  that  sent  out  by  the  generators, 
which  is  obviously  impossible.  The  second 
table  also  shows  the  influence  of  the  air  tem- 
perature upon  the  total  resistance.  The  third 
table  gives  the  power,  and  the  fourth  the 
efficiencies  in  percentages.  It  will  be  noticed 
that  when  one  generator  and  one  motor  only 
were  used,  the  commercial  efficiency  was 
slightly  over  sixty-eight  per  cent.;  but  when 
both  generators  and  both  motors  were  used, 
this  efficiency  rose  to  about  seventy-five  pel- 
cent.,  which  is  clearly  due  to  the  higher  volt- 
age employed. 


I.  —  ELECTRICAL  MEASUREMENTS. 

i 

III.—  DETERMINATION  OK  EXERIIY. 

Time  of 
trial. 

Electromotive 
force. 

Terminal  press- 
ure. 

Current  meas- 
ured at 

Time  of 
trial. 

Internal 
electrical  horse- 
power. 

Terminal 
electrical  horse- 
power. 

Actual  horse- 
power. 

Genera- 
tors. 

Motors. 

Genera- 
tors. 

Motors. 

Genera- 
tors. 

Motors. 

Gener- 
ators. 

Motors. 

Gener- 
ators. 

Motors. 

Suppliei 
to  gen- 
erators. 

Obtained 
from 

motors. 

llth  Oct. 
12th    ' 

1231.6 
1237.0 
1836.5 
2129.0 

988.6 
1016.8 
1575.4 
1896.2 

1177.7 
1186.8 
1753.3 
2058.0 

1041.2 
1066.1 
1656.1 
1965.1 

14.20 
13.24 
11.48 
9.78 

14.17 
13.28 
11.42 
9.79 

llth  Oct. 

12th    " 

tt       it 

23.76 
22.27 
28.64 
28.29 

19.03 
18.34 
24.46 
25.21 

22.72 
21.35 
27.34 
27.37 

20.02 
19.23 
25.71 
26.13 

26.15 
24.54 
30.87 

30.87 

17.85 
16.74 
23.21 
28.06 

II.  —  RESISTANCES  AND  Loss  OF  PRESSURE. 

IV.  —  PERCENTAGE  OF  EFFICIENCIES. 

Time  of 
trial. 

Electrical 
efficiency. 

Commercial 
efficiency. 

Total  effici- 
ency of 
transmission 

Remarks. 

Time  of 
trial. 

Resistance  of 
machines. 

resist- 
ance. 

Pressure  lost  in 
line. 

Temperature 
of  air  centi- 
grade. 

Gener- 
ators. 

Motors. 

Gener- 
ators. 

Motors. 

llth  Oct.      90.7 

"       "         90.6 
12th    "         92.8 

: 

"         91.6 

93.7 

91.3 
94.8 

!H.4 

86.8 

86.9 

88.5 

88.7 

89.1 

87.1 
90.3 

88.8 

63.3    [ 

68.2 
75.2 

74.6 

)       One 
genera- 
•  tor  and 
one 
motor. 
Both 
genera- 
tors and 
both 
motors. 

Genera- 
tors. 

Motors. 

Calcu- 
lated. 

Meas- 
ured. 

llth  Oct. 

*«            (f 

12th    " 

o          << 

3.741 
3.741 
7.251 
7.240 

3.716 
3.710 
7.060 
7.042 

9.228 
9.228 
9.044 
9.040 

130.9 
122.3 
103.7 

88.4 

136.5 

120.7 
97.2 
92.8 

+  7.5 
+  7.5 
+  3.2 
+  3.2 

CHAPTER   XV. 


ALTERNATING,   CURRENT   MOTORS. 


AT  the  time  that  the  authors  began  the 
present  work,  the  electric  motor  had  only 
been  thought  of  in  connection  with  continuous 
currents,  which  then  occupied  almost  exclu- 
sively the  attention  of  those  interested  in  the 
distribution  of  electricity.  Since  that  period, 
however,  the  distribution  of  electricity  by 
means  of  alternating  currents  has  reached  very 
large  proportions,  especially  in  this  country. 
While,  at  first,  the  alternating  current  was  only 
employed  for  the  purpose  of  lighting,  it  soon 
became  evident  that,  in  order  to  attain  the  full 
scope  of  its  usefulness,  it  must  also  be  made 
available  for  the  distribution  of  power.  In 
other  words,  it  became  necessary  to  construct 
alternating  current  motors. 

As  far  back  as  the  year  1868,  Wilde,  in  ex- 
perimenting upon  alternate  current  machines, 
discovered  that  they  could  be  coupled  together 
in  parallel  without  interfering  with  each  other. 
Me  also  tried  the  experiment  of  coupling  two 
machines  together  and  driving  one  as  a  gener- 
ator, which  delivered  its  current  to  the  other, 
the  field  magnets  of  both  being  independently 
excited.  On  placing  the  stationary  armature, 
with  its  coil,  in  a  suitable  position,  in  relation 
to  the  magnet-cylinder  for  producing  electro- 
magnetic rotation,  and  setting  the  generator 
armature  in  motion,  the  motor  armature  with 
its  coil  oscillated  rapidly  in  arcs  of  very  small 
amplitude,  the  oscillations  corresponding  in 
number  with  the  alternations  of  the  current. 
As  the  amplitude  of  the  oscillations  in  this 
experiment  was  limited  by  the  inertia  of 
the  arma.ture,  and  in  order  that  the  effect  of 
one  pulsation  only  on  the  armature  might  be 
observed,  contact  was  made  and  broken  sud- 
denly between  the  connections  by  a  kind  of  tap- 
ping motion,  with  the  result  that  the  stationary 
armature  was  suddenly  jerked  around  nearly  a 


quarter  of  a  revolution,  sometimes  in  the  direc- 
tion in  which  it  would  have  been  driven  by  the 
belt  and  at  other  times  in  the  opposite  direction, 
according  to  the  polarity  of  the  alternating 
wave  which  happened  to  pass  at  that  instant. 

These  experiments,  which  were  published  in 
iheP7iilosophical  Magazine  for  January,  1869, 
attracted  little  attention,  and  had  almost  been 
forgotten  until  recalled  by  a  paper  read  by  Dr. 
John  Hopkinson  before  the  London  Institution 
of  Civil  Engineers  in  1883,  on  "Electric  Light- 
ing," in  which  he  deduced  theoretically  the 
results  obtained  experimentally  by  Wilde. 

Although  the  motor  effect  obtained  by  Wilde 
consisted  only  in  the  oscillation  of  the  arma- 
ture, Dr.  Hopkinson  showed  that  continuous 
revolution  could  be  maintained.  Without  en- 
tering here  into  a  full  treatment  of  the  subject, 
it  may  be  stated  generally  that  the  required 
conditions  under  which  this  takes  place  are 
that  the  lag  of  electromotive  force  of  one  ma- 
chine behind  that  of  the  other  shall  be  greater 
than  a  quarter  period,  the  lag  of  the  current 
being  as  usual  either  equal  to  or  less  than  a 
quarter  period  behind  the  resultant  E.  M.  F. 
Another  result  arrived  at  was  that  one  machine 
can  be  driven  as  a  motor  by  another  even  if  its 
E.  M.  P.  is  greater  than  that  of  the  latter. 

Subsequently,  Dr.  Hopkinson,  in  conjunction 
with  Prof.  W.  G.  Adams,  verified  these  con- 
clusions experimentally  on  three  large  De  Mer- 
itens  alternating  machines  at  the  South  Fore- 
land light-house,  during  their  investigation  on 
"Light-House  Illuminants."*  In  those  exper- 
iments, two  of  the  machines  were  connected  in 
parallel  and  clutched  together  until  they  had 
attained  their  usual  speed,  when  they  were 

*For  a  full  description  of  these  experiments  the  reader  is 
referred  to  a  paper  read  by  Prof.  W.  tr.  Adams  before  the  Soc. 
of  Tel.  Eng.  &  Elecns.  Nov.  13,  1884,  entitled  "The  Alternate 
Current  Machine  as  a  Motor.1'  . 


256 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


unclutclied  and  each  was  driven  by  its  own 
belt.  The  E.  M.  F.  on  open  circuit  remained 
steady — the  machines  continuing  to  rotate  in 
unison — and  was  the  same  as  that  of  one  of  the 
machines  when  tested  by  itself.  No  current 
passed  along  the  connecting  wires.  The  cir- 
cuit was  now  closed  through  an  arc  lamp  ;  the 
machines  continued  to  run  as  steadily  as  be- 
fore, although  a  large  current  of  221  amperes 
was  passing  through  the  arc.  Lastly,  the  lamp 
circuit  was  broken,  the  machines  were  short- 
circuited  on  one  another,  and  the  belt  was 
thrown  off  one  of  them.  It  continued  to  run 
at  the  same  steady  speed,  being  driven  as  a 
motor  by  the  current  from  the  other  machine. 
Other  experiments  were  made,  all  confirming 
the  theoretical  conclusions,  but  their  enumera- 
tion is  needless  and  would  lead  us  too  far. 
We  can  only  refer  the  reader  to  the  original 
papers  and  to  Professor  S.  P.  Thompson' s  work 
on  "Dynamo-Electric  Machinery,"  which  con- 
tains an  excellent  summary  of  them,  as  above 
outlined. 

The  experimenters  also  showed  that  the  speed 
of  a  motor  running  thus  is  perfectly  steady,  but 
is  accompanied  by  the  serious  disadvantages 

(1)  that  the  motor  can  only  run  at  one  speed, 
which  depends  on  the  speed  of  the  generator ; 

(2)  that  it  has  to  be  brought  up  to  this  speed 
by  some  extraneous  means  before  it  can  be  run 
as  a  motor  at  all ;  (3)  that  if  any  of  the  con- 
ditions (such,  for  instance,  as  the  load  being 
too  great)  are  unfavorable  it  pulls  up  and  stops 
altogether.     One  way  of  bringing  the  motor 
up  to  the  required  speed  was  to  drive  it  by  a 
belt  until  the  right  pitch  is  attained  and  then 
to  throw  the  belt  off.     Another  method  em- 
ployed was  to  start  the  generator  slowly  and 
turn  the  motor  by  hand  until  it  fell  into  step 
with  the  generator  ;  the  speed  of  the  latter  was 
then  increased,  when  it  was  found  that  the 
motor  also  increased  its  speed,  keeping  pace 
exactly  with  the  generator.    This,  of  course, 
involves  the  serious  disadvantage  of  having  to 
stop  or  at  least  slow  down  the  generator  every 
time  the  motor  has  to  be  started. 

Although  the  feasibility  of  operating  alter- 
nate current  motors  was  thus  established, 
the  subject,  as  stated  above,  called  for  little 
attention,  however,  until  the  general  intro- 


duction of  the  alternating  current  system  of 
distribution.  One  of  the  first  to  recognize  the 
importance  and  value  of  such  a  machine  was 
Profess  >r  Elihu  Thomson,  who,  in  a  classical 
paper  read  before  the  American  Institute  of 
Electrical  Engineers  in  May,  1887,  entitled 
"Novel  Phenomena  of  Alternating  Currents," 
drew  attention  prominently  to  the  subject  and 
described  some  entirely  new  forms. 

It  is  well  known  that  an  alternating  current 
passing  in  a  coil  or  conductor  laid  parallel  with, 
or  in  inductive  relation  to,  a  second  coil  or  con- 
ductor, will  induce  in  the  second  conductor,  if 
on  open  circuit,  alternating  electromotive 
forces,  and  that  if  its  terminals  be  closed  or 
joined,  alternating  currents  of  the  same 
rhythm,  period  or  pitch,  will  circulate  in  the 
second  conductor.  This  is  the  action  occur- 
ring in  any  induction  coil  whose  primary  wire 
is  traversed  by  alternating  currents,  and  whose 
secondary  wire  is  closed  either  upon  itself 
directly  or  through  a  resistance. 

In  1884,  while  preparing  for  the  International 
Electrical  Exhibition  at  Philadelphia, Professor 
Thompson  had  occasion  to  construct  a  large 
electro-magnet,  the  cores  of  which  were  about 
six  inches  in  diameter  and  about  twenty  inches 
long.  They  were  made  of  bundles  of  iron  rod 
of  about  -^  inch  diameter.  When  complete  the 
magnet  was  energized  by  the  current  of  a  dyna- 
mo giving  continuous  currents,  and  it  exhibited 
the  usual  powerful  magnetic  effects.  It  was 
found  also  that  a  disc  of  sheet  copper,  of  about 
TV  inch  thickness  and  ten  inches  in  diameter, 
if  dropped  flat  against  a  pole  of  the  magnet, 
would  settle  down  softly  upon  it,  being  re- 
tarded by  the  development  of  currents  in  the 
disc  due  to  its  movement  in  a  strong  magnetic 
field,  and  which  currents  were  of  opposite 
direction  to  those  in  the  coils  of  the  mag- 
net. In  fact,  it  was  impossible  to  strike  the 
magnet  pole  a  sharp  blow  with  the  disc  even 
when  the  attempt  was  made  by  holding  one 
edge  of  the  disc  in  the  hand -and  bringing 
it  down  forcibly  towards  the  magnet.  In 
attempting  to  raise  the  disc  quickly  off  the 
pole,  a  similar  but  opposite  action  of  resist- 
ance to  movement  took  place,  showing  the 
development  of  currents  in  the  same  direc- 
tion to  those  in  the  coils  of  the  magnet,  and 


ALTERNATING  CURRENT  MOTORS. 


257 


which  currents,  of  course,  would  cause  attrac- 
tion as  a.  result. 

The  experiment  was,  however,  varied,  as  in 
Fig.  274.  The  disc  D  was  held  over  the  mag- 
net pole,  as  shown,  and  the  current  in  the 
magnet  coils  cut  off  by  shunting  them.  There 
was  felt  an  attraction  of  the  disc  or  a  dip 
toward  the  pole.  The  current  was  then  put 
on  by  opening  the  shunting-switch  and  a  re- 
pulsive action  or  lift  of  the  disc  was  felt. 


FIG.   274. 

The  actions  just  described  are  what  would 
be  expected  in  such  a  case,  for  when  attrac- 
tion took  place,  currents  had  been  induced 
in  the  disc  D  in  the  same  direction  as  those 
in  the  magnet  coils  beneath  it,  and  when  re- 
pulsion took  place,  the  induced  current  in 
the  disc  was  of  opposite  character  or  direction 
to  that  in  the  coils. 

Now,  let  us  imagine  the  current  in  the  mag- 
net coils  to  be  not  only  cut  off,  but  reversed 
back  and  forth.  For  the  reasons  just  given  we 
will  find  that  the  disc  D  is  attracted  and  re- 
pelled alternately  ;  for,  whenever  the  currents 
induced  in  it  are  of  the  same  direction  with 
those  in  the  inducing,  or  magnetic  coil,  attrac- 
tion will  ensue,  and  when  they  are  opposite  in 
direction,  repulsion  will  be  produced.  More- 
over, the  repulsion  will  be  produced  when  the 
current  in  the  magnet  coil  is  rising  to  a  maxi- 
mum in  either  direction,  and  attraction  will  be 
the  result  when  the  current  of  either  direction 
is  falling  to  zero,  since  in  the  former  case 
opposite  currents  are  induced  in  the  disc  D  in 
accordance  with  well-known  laws  ;  and  in  the 
latter  case  currents  of  the  same  direction  will 
exist  in  the  disc  D  and  the  magnet  coil.  The 
disc  might,  of  course,  be  replaced  by  a  ring  of 
copper  or  other  good  conductor,  or  by  a  closed 
coil  of  bare  or  insulated  wire,  or  by  a  series  of 


discs,  rings  or  coils  superposed,  and  the  results 
would  be  the  same. 

The  account  just  given  of  the  effects  pro- 
duced by  alternating  currents,  while  true,  is 
not  the  whole  truth,  and  Professor  Thomson 
supplements  it  by  the  following  statements  : 

"An  alternating  current  circuit  or  coil  re- 
pels and  attracts  a  closed  circuit  or  coil  placed 
in  direct  or  magnetic  inductive  relation  there- 
with ;  but  the  repulsive  effect  is  in  excess  of 
the  attractive  effect. 

' '  When  the  closed  circuit  or  coil  is  so  placed, 
and  is  of  such  low  resistance  metal  that  a  com- 
paratively large  current  can  circulate  as  an 
induced  current,  so  as  to  be  subject  to  a  large 
self-induction,  the  repulsive  far  exceeds  the 
attractive  effort." 

Professor  Thomson  calls  this  excess  of  re- 
pulsive effect  the  "electro-inductive  repulsion" 
of  the  coils  or  circuits. 

This  preponderating  repulsive  effect  may  be 
utilized  or  may  show  its  presence  by  producing 
movement  or  pressure  in  a  given  direction,  by 
producing  angular  deflection  as  of  a  pivoted 
body,  or  by  producing  continuous  rotation 
with  a  properly  organized  structure.  Among 
the  simple  devices  realizing  these  conditions 
are  the  following : 


KK.  WorU,  X.  Y. 

FIG.  275. 

In  Fig.  275,  C  is  a  coil  traversed  by  alternat- 
ing currents,  B  is  a  copper  case  or  tube  sur- 
rounding it,  but  not  exactly  over  its  centre. 
The  copper  tube  B  is  fairly  massive  and  is  the 
seat  of  heavy  induced  currents.  There  is  a 
preponderance  of  repulsive  action  tending  to 
force  the  two  conductors  apart  in  an  axial  line. 
The  part  B  may  be  replaced  by  concentric 
tubes  slid  one  in  the  other,  or  by  a  pile  of  flat 
rings,  or  by  a  closed  coil  of  coarse  or  fine  wire 


258 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


insulated,  or  not.  If  the  coil  C,  or  primary 
coil,  is  provided  with  an  iron  core  (such  as  a 
bundle  of  line  iron  wires),  the  effects  are  greatly 
increased  in  intensity  and  the  repulsion  with  a 
strong  primary  current  may  become  quite  vig- 
orous, many  pounds  of  thrust  being  producible 
by  apparatus  of  quite  moderate  size. 


FIG.  276. 

The  forms  and  relations  of  the  two  parts  C 
and  B  may  be  greatly  modified  with  the  gen- 
eral result  of  a  preponderance  of  repulsive 
action  when  the  alternating  currents  circulate. 

It  will  be  evident  that  the  repulsive  actions 
will  not  be  mechanically  manifested  by  axial 
movement  or  effort,  when  the  electrical  middles 
of  the  coils  or  circuits  are  coincident.  In 
cylindrical  coils  in  which  the  current  is  uni- 
formly distributed  through  all  the  parts  of  the 
conductor  section,  what  Professor  Thomson 
terms  the  "electrical  middle,"  or  the  centre  of 
gravity  of  the  ampdre  turns  of  the  coils,  will 
be  the  plane  at  right  angles  to  its  axis  at  its 
middle. 

If  the  iron  core  takes  the  form  of  that  shown 
by  77,  Fig.  276,  such  as  a  cut  ring  with  the 
coil  C  wound  thereon,  the  insertion  of  a  heavy 
copper  plate  B  into  the  slot  or  divided  portion 
of  the  ring  will  be  opposed  by  a  repulsive  effort 
when  alternating  currents  pass  in  C.  This 
was  the  first  form  of  device  in  which  Professor 
Thomson  noticed  the  phenomenon  of  repul- 
sive preponderance  in  question.  The  tendency 
is  to  thrust  the  plate  B  out  of  the  slot  in  the 
ring  excepting  only  when  its  centre  is  coinci- 
dent with  the  magnetic  axis  joining  the  poles 
of  the  ring  between  which  B  is  placed. 


We  will  now  turn  our  attention  to  the  ex- 
planation  of  the  actions  exhibited,  and  after- 
wards refer  to  their  applications.  It  may  be 
stated  as  certainly  true  that  were  the  induced 
currents  in  the  closed  conductor  unaffected  by 
any  self-induction,  the  only  phenomena  exhib- 
ited would  be  alternate  equal  attractions  and 
repulsions,  because  currents  would  be  induced 
in  opposite  directions  to  that  of  the  primary 
current  when  the  latter  current  was  changing 
from  zero  to  maximum  positive  or  negative 
current,  so  producing  repulsion  ;  and  would  be 
induced  in  the  same  direction  when  changing 
from  maximum  positive  or  negative  value  to 
zero,  so  producing  attraction. 

This  condition  can  be  illustrated  by  a  dia- 
gram, Fig.  277.  Here  the  lines  oT  zero  current 
are  the  horizontal  straight  lines.  The  wavy 
lines  represent  the  variations  of  current 
strength  in  each  conductor,  the  current  in  one 
direction  being  indicated  by  that  portion  of  the 
curve  above  the  zero  line,  and  in  the  other 
direction  by  that  portion  below  it.  The  verti- 
cal dotted  lines  simply  mark  off  corresponding 
portions  of  phase  or  succession  of  times. 


K—L I_O--| X. 1 l-.it.-4-- -4- . 


Here  it  will  be  seen  that  in  the  positive  pri- 
mary current  descending  from  in,  its  maximum, 
to  the  zero  line,  the  secondary  current  lias  risen 
from  its  zero  to  ml,  its  maximum.  Attraction 
will  therefore  ensue,  for  the  currents  are  in  the 
same  direction  in  the  two  conductors.  When 
the  primary  current  increases  from  zero  to  its 
negative  maximum  n,  the  positive  current  in 


ALTERNATING   CURRENT   MOTOES. 


259 


the  secondary  closed  circuit  will  be  decreasing 
from  TO1,  its  positive  maximum,  to  zero  ;  but, 
as  .the  currents  are  in  opposite  directions,  re- 
pulsions will  occur.  These  actions  of  attraction 
and  repulsion  will  be  reproduced  continually, 
there  being  a  repulsion,  then  an  attraction, 
then  a  repulsion,  and  again  an  attraction,  dur- 


FIG.  278. 

ing  one  complete  wave  of  the  primary  current. 
The  letters  r,  a,  at  the  foot  of  the  diagram, 
Fig.  277,  indicate  this  succession. 

In  reality,  however,  the  effects  of  self-induc- 
tion in  causing  a  lag,  shift,  or  retardation  of 
phase  in  the  secondary  current,  will  consider- 
ably modify  the  results  and  especially  so  when 
the  secondary  conductor  is  constructed  so  as 
to  give  to  such  self-induction  a  large  value.  In 
other  words,  the  maxima  of  the  primary  or 
inducing  current  will  no  longer  be  found  coin- 
cident with  the  zero  points  of  the  secondary 
currents.  The  effect  will  be  the  same  as  if  the 
line  representing  the  wave  of  the  secondary 
current  in  Fig.  277  had  been  shifted  forward  to 
a  greater  or  less  extent.  This  is  indicated  in 
diagram,  Fig.  278.  It  gives  doubtless  an  ex- 
aggerated view  of  the  action,  though  from  the 
effects  of  repulsion  which  have  been  produced 
it  is  by  no  means  an  unrealizable  condition. 

It  will  be  noticed  that  the  period  during 
which  the  currents  are  opposite,  and  during 
which  repulsion  can  take  place,  is  lengthened 
at  the  expense  of  the  period  during  which  the 
currents  are  in  the  same  direction  for  attractive 
action.  These  differing  periods  are  marked  r,  a, 


etc.,  or  the  period  during  which  repulsion  exists 
is  from  the  zero  of  the  primary  or  inducing  cur- 
rent to  the  succeeding  zero  of  the  secondary  or 
induced  current ;  and  the  period  during  which 
attraction  exists  is  from  the  zero  of  the  induced 
current  to  the  zero  of  inducing  current. 

But  far  more  important  still  in  giving  promi- 
nence to  the  repulsive  effect  than  this  differ- 
ence of  effective  period,  is  the  fact  that  during 
the  period  of  repulsion  both  the  inducing  and 
induced  currents  have  their  greatest  values, 
while  during  the  period  of  attraction  the  cur- 
rents are  of  small  amounts  comparatively. 
This  condition  may  be  otherwise  expressed  by 
saying  that  the  period  during  which  repulsion 
occurs  includes  all  the  maxima  of  current, 
while  the  period  of  attraction  includes  no 
maxima.  There  is  then  a  repulsion  due  to  the 
summative  effects  of  strong  opposite  currents 
for  a  lengthened  period,  against  an  attraction 
due  to  the  summative  effects  of  weak  currents 
of  the  same  direction  during  a  shortened 
period,  the  resultant  effect  being  a  greatly 
preponderating  repulsion. 

It  is  now  not  difficult  to  understand  all  the 
actions  before  described  as  obtained  with  the 
varied  relations  of  coils,  magnetic  fields  and 
closed  circuits.  It  will  be  easily  understood, 


FIG.  279. 

also,  that  an  alternating  magnetic  field  is  in  all 
respects  the  same  as  an  alternating  current  coil 
in  producing  repulsion  on  the  closed  conductor, 
because  the  repulsions  between  the  two  con- 
ductors are  the  result  of  magnetic  repulsions 
arising  from  opposing  fields  produced  by  the 
coils  when  the  currents  are  of  opposite  direc- 
tions in  them. 


260 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


This  principle  lias  been  applied  to  the  con- 
struction of  an  alternating  current  motor  which 
can  be  started  from  a  state  of  rest,  and  a  num 
ber  of  designs  of  such  motors  are  practicable. 

One  of  the  simplest  is  as  follows :    The  coils 
(7,  Fig.  279,  are  traversed  by  an  alternating 


Kite.  World,  X.  f. 


FIG.  279A. 

current  and  are  placed  over  a  coil  /?,  mounted 
upon  a  horizontal  axis,  transverse  to  the  axis 
of  the  coil  C.  The  terminals  of  the  coil  S, 
which  is  wound  with  insulated  wire,  are  car- 
ried to  a  commutator,  the  brushes  being  con- 
nected by  a  wire,  as  indicated.  The  commutator 
is  so  constructed  as  to  keep  the  coil  B  on  short 
circuit  from  the  position  of  coincidence  with 
the  plane  of  C,  to  the  position  where  the  piano 
of  B  is  at  right  angles  to  that  of  C ;  and  to 
keep  the  coil  B  open-circuited  from  the  right- 
angled  position,  or  thereabouts,  to  the  position 
of  parallel  or  coincident  planes.  The  deflective 
repulsion  exhibited  by  B  will,  when  its  circuit 
is  completed  by  the  commutator  and  brushes, 
as  described,  act  to  place  its  plane  at  right- 
angles  to  that  of  C,  but  being  then  open- 
circuited  its  momentum  carries  it  to  the  posi- 
tion just  past  parallelism,  at  which  moment  it 
is  again  short-circuited,  and  so  on.  It  is  capa- 
ble of  very  rapid  rotation,  but  its  energy  is 
small.  Professor  Thomson  has,  however,  ex- 
tended the  principle  to  the  construction  of 
more  complete  apparatus.  One  form  has  its 
revolving  portion  or  armature  composed  of  a 
number  of  sheet-iron  discs  wound  as  usual 
with  three  coils  crossing  near  the  shaft.  The 
commutator  is  arranged  to  short-circuit  each 
of  these  coils  in  succession,  and  twice  in  a 


revolution,  and  for  a  period  of  90  degrees  of 
rotation  each.  The  field  coils  surround  the 
armature  and  there  is  a  laminated  iron  field 
structure  completing  the  magnetic  circuit. 

Figs.  279  A  and  279s  will  give  an  idea  of  the 
construction  of  the  motor  referred  to.  C  C1  are 
the  field  coils  or  inducing  coils  which  alone  are 
put  into  the  alternating  current  circuit,  //is 
a  mass  of  laminated  iron,  in  the  interior  of 
which  the  armature  revolves,  with  its  three 
coils  .5,  B2,  J53,  wound  on  a  core  of  sheet-iron 
discs.  The  commutator  short-circuits  the  arma- 
ture coils  in  succession  in  the  proper  positions 
to  utilize  the  repulsive  effect  set  up  by  the 
currents  which  are  induced  in  them  by  the 
alternations  in  the  field  coils.  The  motor  has 
no  dead  point  and  will  start  from  a  state  of 
rest  and  give  out  considerable  power,  but  with 
what  economy  is  not  yet  known. 

A  curious  property  of  the  machine  is  that  at 
a  certain  speed,  depending  upon  the  rapidity 
of  the  alternations  in  the  coil  C,  a  continuous 
current  passes  from  one  commutator  brush  to 
the  other,  and  it  will  energize  electro-magnets 


FIG.  279B. 

and  perform  other  actions  of  direct  currents. 
Here  we  have,  then,  a  means  of  inducing  direct 
currents  from  alternating  currents.  To  control 
the  speed  and  keep  it  at  that  required  for  the 
purpose,  we  have  only  to  properly  gear  the 
motor  to  another  of  the  ordinary  type  for 


ALTERNATING  CURRENT  MOTORS. 


261 


alternating  currents,   namely,    an  alternating 
current  dynamo  used  as  a  motor. 

Taking  up  the  principle  of  electro-inductive 
repulsion  enunciated  by  Professor  Thomson, 
Lieutenant  F.  Jarvis  Patten,  U.  S.  A.,  has  de- 


Fio.  280. 

signed  a  motor  in  which  the  same  principle  is 
reversed,  with  the  apparent  effect  of  producing 
a  more  continuous  rotary  effort  as  well  as  an 
increased  moment  of  rotation  by  virtue  of 
placing  the  point  at  which  the  effort  is  applied 
farther  from  the  axis  of  rotation  and  thereby 
giving  to  the  force  at  work,  however  small,  a 
much  greater  lever-arm.  Figs.  280  and  281  are 
end  and  side  elevations  of  the  machine,  and 
Fig.  282  is  a  diagram  of  circuits  and  connec- 
tions. A  polygonal  frame  FFFis  connected 
by  lateral  strips  N  JV,  and  all  is  supported 
upon  the  base  B  B.  Secured  to  the  lateral 
strips  NN  are  two  sets  of  copper  discs  D  D 
and  d  d.  These  discs  constitute  the  armature 


FIG.  281. 

of  the  machine ;  they  are  arranged  peripher- 
ally, as  shown,  lixed  to  the  frame  structure, 
and  consist  of  circuits  of  high  self-inductive 
capacity  that  remain  permanently  closed. 

A  spindle  x  x,  Figs.  280  and  281,  carries  a 
revolving  switch  Cl  C*,  or  sunflower,  which  is 


secured  to  the  spindle  and  turns  with  it.  This 
sunflower  commutator  constitutes  one  terminal 
of  the  machine,  while  an  insulated  ring  &+, 
and  its  contact  brush  secured  to  the  support 
P  P,  constitutes  the  other.  Under  each  set  of 
discs,  D  D  and  d  d,  and  secured  to  the  spindle 
x,  is  a  set  of  solenoids  ;  those  of  one  set  being 
placed  at  an  angle  of  45  degrees  to  those  of 
the  other  set,  from  which  it  results  that  these 
two  sets  of  solenoids  will  each  come  alternately 
into  action  with  respect  to  its  own  set  of  cop- 
per discs.  Each  set  of  solenoids  has  its  four 
coils  connected  in  series  and  the  two  sets  are 
arranged  in  two  independent  circuits.  Both 
have  one  terminal  secured  to  the  contact  b  +, 
and  the  other  terminal  to  the  alternate  seg- 
ments of  the  revolving  sunflower.  This  system 


FIG.  282. 

of  connections  is  shown  in  Fig.  282,  in  which 
the  eight-part  commutator  is  shown  with  alter- 
nate segments  connected  to  each  other  in  sepa- 
rate series.  The  coils  S1,  S3,  S*,  S\  form  one 
set  of  revolving  solenoids  connected  in  series 
from  the  rubbing  contact  b  +,  which  forms  one 
terminal  of  the  machine,  to  the  commutator 
segment  Cl,  and  thence  to  all  the  odd-num- 
bered segments.  In  like  manner  the  other  set 
of  solenoids  S2,  £4,  Se,  S9,  are  similarly  con- 
nected in  series  to  all  the  even-numbered  seg- 
ments, C12,  <74,  (76,  C*.  From  this  arrangement 
it  results  that,  as  the  spindle  revolves,  carrying 
these  solenoids  as  a  sort  of  fly-wheel,  the  alter- 
nating current  will  be  sent  in  rapid  succession 
first  through  one  set  of  solenoids,  and  then 
through  the  other,  and  by  suitably  placing 
this  commutator  upon  the  spindle  it  can  be 


262 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


made  to  send  the  current  through  the  different 
sets  of  solenoids  during  the  periods  of  maxi 
mum  effort  of  repulsion  between  each  set  and 
its  corresponding  set  of  copper  discs. 

The  moment  of  rotation  is  evidently  a  maxi- 
mum under  this  system  of  construction,  and  by 
increasing  the  number  of  sets  of  solenoids  that 
follow  each  other  in  action,  the  effort  of  the 
rotary  torque  may  be  made  nearly  continuous 
and  constant. 


FIG.  283. 

It  is  evident  that  this  motor  is  not  designed 
for  heavy  work.  Its  efficiency  is  not  high,  and 
its  form  renders  such  an  application  quite  im- 
possible, but  it  can  find  a  place  in  the  smaller 
industries,  where  light  motors  fill  a  definite 
requirement,  and  render  an  alternating  current 
circuit  a  paying  one  during  the  working  hours 
of  the  day. 

In  discussing  the  actions  which  take  place  in 
an  alternating  current  motor,  Dr.  Louis  Dun- 
can, in  a  paper  read  before  the  American 
Institute  of  Electrical  Engineers  in  February, 
1888,  considers  the  case  of  an  alternating  cur- 
rent motor  built  like  an  alternating  dynamo,  the 
field  excited  by  a  continuous  current.  If  A  B  C, 
Fig.  283,  are  the  poles  of  the  field  magnets,  sup- 
posed to  be  excited  by  a  continuous  current,  then 
the  curve  //will  represent  the  counter  or  motor 
E.  M.  F.  If  the  motor  is  running  slowly  there 
will  be  two  or  three  reversals  of  current  in  the 
time  it  takes  a  coil  to  go  from  A  to  B,  Fig.  284, 
and  the  product  C  E  will  be  nearly  zero,  the 
positive  and  negative  parts  being  almost  equal. 
Whether  it  is  -f  or  —  is  somewhat  a  matter  of 
chance,  and  if  it  is  —  from  A  to  B  it  is  very 
likely  to  be  +  from  B  to  C.  Thus  the  arma- 
ture is  pushed  first  in  one  direction,  then  in  the 
opposite,  and  there  is  no  definite  tendency  for 
it  to  rotate  as  a  motor.  This  brings  us  to  the 
first  difficulty,  viz.,  a  simple  alternating  current 
motor  will  not  start  itself.  Let  us  suppose, 
however,  that  it  has  been  started  by  some 


means  and  has  reached  such  a  speed  that  in 
the  time  of  a  reversal  a  coil  shall  have  moved 
over  the  distance  between  two  similar  poles. 
We  will  have  the  state  of  things  in  Fig.  283, 
and  the  armature  will  continue  to  rotate.  Now 
the  position  of  the  curve  //  is  fixed ;  we  will 
consider  the  position  of  /as  determined  by  the 
position  of  the  armature  coils  when  the  current 
in  them  is  zero ;  for  instance,  if  the  speed  in- 
creases a  little  the  curve  will  advance  as  shown 
by  the  dotted  line.  The  total  work  trans- 
formed is  the  product  of  the  two  curves  ;  from 
1  to  2  it  is  — ;  from  2  to  3  it  is  +  ;  from  3  to  4 
- ;  from  4  to  5  +.  The  result  is,  —  [1  to  2  + 
3  to  4]  ;+  [2  to  3  +  4  to  5]  ;  part  of  the  time 
then  the  machine  is  working  as  a  dynamo, 
part  of  the  time  as  a  motor ;  the  difference  of 
the  values  represented  by  the  brackets  gives 
the  mechanical  work  that  is  really  available. 
Now  while  the  available  work  is  the  difference 
of  these  areas,  the  difference  becoming  small  as 
the  load  is  decreased,  the  heating  is  the  sum 
C2  R  for  all  the  values  of  the  current,  and  is 
independent  of  the  position  of  its  curve. 

Looking  at  the  figure  again,  we  see  that  from 
1  to  2  the  armature  is  pushed  forward  by  the 
current  in  the  line  ;  from  2  to  3  it  is  pulled 
back,  since  it  is  acting  as  a  dynamo  feeding 
into  the  line,  and  can  only  get  the  energy  to 
produce  the  current  by  decreasing  its  speed 
and  drawing  from  its  energy  of  motion.  The 
armature  oscillates  then,  and  it  is  evident  that 
the  amount  of  its  oscillation  depends  on  the 


FIG.  284. 

kind  of  work  it  is  doing.  If  it  is  driving  heavy 
wheels  or  machinery  having  considerable  in- 
ertia, it  will  only  have  to  slow  down  slightly 
when  it  becomes  a  dynamo.  If  it  is  lifting 
weights,  the.  amount  of  oscillation  will  be  con- 
siderable. 

It  is  evident  that  there  is  a  certain  position 
of  the  curve  /  that  will  make  the  available 
work  a  maximum.  If  the  motor  is  do*ng  all 
of  its  possible  work  the  curve  will  take  up  this 


ALTERNATING  CURRENT  MOTORS. 


263 


position  ;  as  the  load  is  decreased  the  speed 
will  increase  for  an  instant  until  the  curve  has 
shifted  forward  into  such  a  position  that  the 
sum  of  the  products — E  C — is  equal  to  the 
work  done.  In  fact,  we  can  plat  a  curve  repre- 
senting values  of  the  distance  from  the  point 
the  current  curve  crosses  the  axis  to  the  same 
point  when  the  work  is  zero  corresponding  to 
different  loads. 

Now  the  value  of  this  lag  cannot  be  greater 
than  Op,  Fig.  285,  for  although  we  might  ex- 


Load 


tend  our  curve  on  the  other  side,  yet  a  slight 
increase  in  our  load  will  cause  the  armature  to 
fall  back,  decreasing  the  available  work,  and 
suddenly  stop.  It  is,  in  fact,  in  unstable  equi- 
librium. 

Suppose  we  have  found  the  value  of  the  lag 
that  will  give  us  a  maximum  value  of  the 
work,  and  have  calculated  this  vahie  by  the 
ordinary  mathematical  methods  employed,  the 
real  work  we  can  obtain  is  less  than  this,  for 
the  current  curve  oscillates  on  both  sides  of  the 
maximum,  supposing  we  could  work  at  the 
maximum  ;  that  is,  it  is  only  for  a  very  short 
time  in  the  best  position  ;  so  that  if  we  take 
the  sum  of  the  work  for  a  period,  it  will  be  less 
than  the  calculated  maximum.  In  reality  we 
must  work  slightly  in  advance  of  the  maxi- 
mum, for  if  we  were  too  near  it  the  curve 
would  fall  behind  P,  and  will  then  be  in  un- 
stable equilibrium  and  stop.  The  practical 
maximum  will  then  vary  according  to  the 
amount  of  the  oscillation  ;  that  is,  according  to 
the  nature  of  the  work  being  done. 

Dr.  Duncan,  in  discussing  the  possible  forms 
of  alternating  current  motors,  suggested  the 
following :  (1)  An  ordinary  series  motor ;  (2) 
an  alternating  dynamo  reversed,  the  field  be- 
ing excited  by  a  continuous  current ;  (3)  an 
alternating  dynamo  reversed,  the  field  being 
excited  by  the  alternating  current  first  cor- 


rected by  a  commutator  on  the  shaft ;  (4)  the 
arrangement  suggested  by  Professor  Thomson, 
which  has  been  described  above. 

In  the  first  type — a  series  motor — there  is  no 
difficulty  in  starting  ;  the  motor  will  start  of 
itself.  There  are  these  difficulties,  however : 
the  armature  and  field  must  both  b3  thoroughly 
laminated  to  prevent  eddy  currents  ;  the  mag- 
netism of  such  large  masses  of  iron  being  rap- 
idly reversed  will  cause  losses  unless  both  field 
and  armature  are  far  from  saturation  ;  that  is, 
the  mass  must  be  great.  Again,  Mr.  Kapp  has 
shown  that  to  obtain  the  maximum  work  we 
must  have,  approximately,  the  counter  E.  M.  F. 
of  the  motor  equal  to  the  E.  M.  F.  of  self- 
induction — a  condition  almost  impossible  to 
realize  in  practice.  The  motor  must  be  gov- 
erned in  some  way,  as  it  will  not  govern  itself. 

The  alternating  motor,  with  a  field  fed  from 
the  alternating  circuit,  the  current  being  com- 
mutated,  will  start  itself.  If,  in  Fig.  286,  A 
and  B  are  poles  and  C  one  of  the  armature 
coils,  the  effects  of  the  currents  will  be  as 
shown  by  the  two  sets  of  signs.  The  effect  of 
either  arrangement  is  to  move  the  armature  in 
the  direction  of  the  arrow.  When  C  gets  op- 
posite A  the  commutator  changes  the  relative 
directions  of  the  currents  in  C  and  A,  and  <7is 
repelled  by  A  and  the  armature  continu.es  to 
rotate.  The  maximum  work  will,  according  to 
Dr.  Duncan,  be  done  when  the  speed  is  such 
that  a  reversal  takes  place  in  a  distance  A  to 


FIG.  286. 

B.  There  is  an  advantage  in  this  type  in  that 
it  will  start  itself  ;  a  disadvantage  is  that  the 
fields  must  be  carefully  laminated;  there  is  loss 
in  reversing  them,  and  there  will  be  for  some 
speeds  considerable  sparking  at  the  field  com- 
mutator. It  is  probable,  also,  that  the  work 
obtainable  from  such  a  motor  would  not  be  as 
great  as  if  its  field  were  fed  by  continuous  cur- 
rents. 

The  motor  obtained  by  reversing  an  ordinary 
alternating  dynamo  has  advantages  and  disad- 


264 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


vantages.  It  perfectly  regulates  itself,  and  the 
field  magnets  need  not  be  laminated  ;  that  is, 
it  can  be  made  cheaply.  It  will  give  a  greater 
output  from  a  given  source  of  current  than 
corresponding  machines  of  either  of  the  types 
already  discussed.  Its  disadvantages  are  that 
it  must  be  started  independently.  We  must 
have  a  continuous  current  to  excite  the  field, 
and  if  a  load  having  any  considerable  inertia 
be  suddenly  applied  the  motor  will  stop.  This 
last  objection  also  applies  to  the  type  of  motor 
mentioned  above,  provided  the  maximum  work 
is  obtainable  when  the  counter  E.  M.  F.  has 
the  same  period  as  the  applied  E.  M.  F. 

The  motor  might  be  started  by  passing  the 
commutated  alternating  current  through  the 
field  as  in  the  second  type  of  motor  discussed, 
changing  our  connections  when  the  proper 
speed  is  attained,  so  that  a  continuous  current 
from  some  external  source  passes  through  the 
field,  and  the  alternating  current  is  shut  off 
from  it.  Another  way  would  be  to  have  on 
the  same  shaft  with  the  main  motor  a  motor 
arrangement  similar  to  that  of  Professor  Elihu 
Thomson,  described  above.  With  this  arrange- 
ment we  can  do  more  than  start  the  motor.  It 
was  pointed  out  that  when  this  auxiliary 
motor  reached  a  certain  speed  it  would  pro- 
duce a  continuous  current  in  the  external  cir- 
cuit of  its  armature.  This  current  could  be 
used  to  excite  the  field  of  the  main  motor.  By 
properly  proportioning  the  number  of  coils  in 
the  main  and  auxiliary  motors,  this  continuous 
current  would  be  produced  just  when  the  motor 
had  arrived  at  its  proper  speed,  and  it  is  evident 
that  we  can  make  this  current  operate  an  auto- 
matic device  to  make  the  circuit  of  the  main  mo- 
tor at  this  moment.  According  to  Dr.  Duncan, 
however,  a  motor  made  in  this  way  would  be 
expensive  and  not  particularly  efficient. 

Dr.  Duncan  considers  the  simplest,  cheapest 
and  most  efficient  means  of  running  alternating 
current  motors  is  this  :  Build  the  motor  on  the 
same  general  plan  as  the  dynamo,  with  such 
modifications  as  the  different  conditions  of 
working  impose,  and  start  it  and  excite  the 
field  magnets  from  a  continuous  current  cir- 
cuit, run  with  the  alternating  circuit,  supplied 
with  current  by  a  dynamo  at  the  central  sta- 
tion. If  it  is  desired  to  distribute  500  horse- 


power the  continuous  circuit  should  have  a 
maximum  capacity  of  about  50  horse-power. 
To  start  the  motor  the  following  arrangement 
would  be  used :  There  should  be  two  breaks 
in  the  armature  circuit,  one  between  the  regu- 
lar brushes  of  the  machine,  the  other  as  a  com- 
mutator for  the  continuous  current.  At  this 
second  break  the  two  ends  of  the  circuit  should 
be  taken  to  alternate  bars  of  the  commutator, 
the  number  of  bars  being  such  that  the  direc- 
tion of  the  current  is  reversed  every  time  a 
coil  passes  a  pole.  The  alternate  bars  arc  nor- 
mally connected  by  a  metal  rin^1  pressed 
against  them  by  a  spring  ;  in  this  case  we  will 
have  the  normal  circuit  just  as  if  there  were 
no  continuous  current  commutator.  On  the 
motor  would  be  a  switch-board  that  would 
accomplish  the  following  things  :  If  we  wish 
to  start  we  turn  the  handle  of  the  switch  to  a 
certain  position;  this  will  short-circuit  our  reg- 
ular brushes  and  by  the  aid  of  a  couple  of 
levers  will  drop  the  continuous  circuit  brushes 
on  the  commutator,  at  the  same  time  pulling 
away  the  metal  ring.  The  motor  will  then 
start  as  a  continuous  current  motor.  When  it 
has  reached  its  proper  number  of  revolutions, 
or  is  above  it,  turn  the  handle  a  little  further  ; 
the  continuous  current  brushes  will  be  raised, 
the  metal  ring  will  connect  the  commutator 
bars  and  the  alternating  circuit  will  be  made, 
and  the  motor  will  continue  to  run  and  will  do. 
work. 

In  enumerating  the  various  methods  which 
might  be  employed  in  the  construction  of  alter- 
nating current  motors,  Mr.  Nikola  Tesla,  in  a 
masterly  paper  read  before  the  American  Insti- 
tute of  Electrical  Engineers  in  May,  1888,  re- 
ferred to  those  given  by  Dr.  Duncan  as  stated 
above,  and  suggested  two  additional  ones,  viz. : 
(1)  A  motor  with  one  of  its  circuits  in  series 
with  a  transformer  and  the  other  in  the  second- 
ary of  the  transformer  ;  (2)  a  motor  having  its 
armature  circuit  connected  to  the  generator 
and  the  field  coils  closed  upon  themselves. 
These,  however,  were  only  incidentally  men- 
tioned by  Mr.  Tesla.  the  paper  relating  to  an 
entirely  new  class  of  alternate  current  motors, 
based  upon  the  continuous  rotation  of  the 
magnetic  poles  in  a  closed  magnetic  circuit, 
and  which  we  will  now  proceed  to  describe. 


ALTERNATING  CURRENT  MOTORS. 


265 


In  dynamo  machines,  it  is  well  known,  we 
generate  alternate  currents  which  we  direct  by 
means  of  a  commutator.  Now,  the  currents  so 
directed  cannot  be  utilized  in  the  motor,  but  they 
must  again  be  reconverted  into  their  original 
state  of  alternate  currents.  The  function  of 
the  commutator  is  entirely  external,  and  in  no 
way  does  it  affect  the  internal  working  of  the 
machines.  In  reality,  therefore,  all  machines 
are  alternate-current  machines,  the  currents 
appearing  as  continuous  only  in  the  external 
circuit  during  their  transit  from  generator  to 
motor.  But  the  operation  of  the  commutator 
on  a  motor  is  two-fold  ;  first,  it  reverses  the 
currents  through  the  motor,  and  secondly,  it 
effects,  automatically,  a  progressive  shifting  of 
the  poles  of  one  of  its  magnetic  constituents. 
Assuming,  therefore,  that  both  of  these  opera 
tions  in  the  system — that  is  to  say,  the  direct- 


FIG.  287. 

ing  of  the  alternate  currents  on  the  generator 
and  reversing  the  direct  currents  on  the  motor 
—be  eliminated,  it  would  still  be  necessary,  in 
order  to  cause  a  rotation  of  the  motor,  to  pro- 
duce a  progressive  shifting  of  the  poles  of  one 
of  its  elements,  and  the  question  presented 
itself  to  Mr.  Tesla,  How  to  perform  this  opera- 
tion by  the  direct  action  of  alternate  currents  ? 
Wo  will  now  proceed  to  show  how  this  result 
was  accomplished. 

In  the  first  experiment,  a  drum-armature  was 
provided  with  two  coils  at  right  angles  to  each 
other,  and  the  ends  of  these  coils  were  connected 
to  two  pairs  of  insulated  contact-rings  as  usual. 
A  ring  was  then  made  of  thin  insulated  plates 
of  sheet-iron  and  wound  with  four  coils,  each 
two  opposite  coils  being  connected  together  so 
as  to  produce  free  poles  on  diametrically  oppo- 
site sides  of  the  ring.  The  remaining  free  ends 
of  the  coils  were  then  connected  to  the  contact- 


rings  of  the  generator-armature  so  as  to  form 
two  independent  circuits,  as  indicated  in  Fig. 
287.  The  field  of  the  generator  being  inde- 
pendently excited,  the  rotation  of  the  armature 
sets  up  currents  in  the  coils  CC,  Fig.  288,  vary- 
ing in  strength  and  direction  in  the  well  known 
manner.  In  the  position  shown  in  Fig.  288  the 
current  in  coil  Gyis  nil  while  coil  C  is  traversed 


Fio.  288. 

by  its  maximum  current,  and  the  connections 
may  be  such  that  the  ring  is  magnetized  by 
the  coils  e,  <?j  as  indicated  by  the  letters  JV S 
in  Fig.  288A,  the  magnetizing  effect  of  the  coils 
c  c  being  nil,  since  these  coils  are  included  in 
the  circuit  of  coil  C. 

In  Fig.  289  the  armature  coils  are  shown  in 
a  more  advanced  position,  one-eighth  of  one 
revolution  being  completed.  Fig.  289 A  illus- 
trates the  corresponding  magnetic  condition  of 
the  ring.  At  this' moment  the  coil  Ct  generates 
a  current  of  the  same  direction  as  previously, 
but  weaker,  producing  the  poles  n^  sl  upon 
the  ring  ;  the  coil  C  also  generates  a  current  of 
the  same  direction,  and  the  connections  may 
be  such  that  the  coils  c  c  produce  the  poles  n  s, 


289.  FIG.  289A. 

as  shown  in  Fig.  289A.  The  resulting  polarity 
is  indicated  by  the  letters  N  S,  and  it  will  be 
observed  that  the  poles  of  the  ring  have  been 
shifted  one-eighth  of  the  periphery  of  the  same. 
In  Fig.  290  the  armature  has  completed  one- 
quarter  of  one  revolution.  In  this  phase  the 
current  in  coil  C  is  a  maximum,  and  of  such 
direction  as  to  produce  the  poles  N  8  in  Fig. 
290 A,  whereas  the  current  in  coil  C",  is  nil,  this 


266 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


coil  being  at  its  neutral  position.  The  poles 
JV  8  in  Fig.  29<>A  are  thus  shifted  one-quarter 
of  the  circumference  of  the  ring. 

Fig.  291  shows  the  coils  C  C  in.  a  still  more 
advanced  position,  the  armature  having  com- 
pleted three-eighths  of  one  revolution.  At 


A 

FIG.  290.  FIG.  290A. 

that  moment  the  coil  C  still  generates  a  cur- 
rent of  the  same  direction  as  before,  but  of  less 
strength,  producing  the  comparatively  weaker 
poles  n  s  in  Fig.  291A.  The  current  in  the  coil 
Cl  is  of  the  same  strength,  but  of  opposite 
direction.  Its  effect  is,  therefore,  to  produce 


FIG.  291. 


FIG.  291  A. 


upon  the  ring  the  poles  nl  and  sl  as  indicated, 
and  a  polarity,  N  S,  results,  the  poles  now  be- 
ing shifted  three-eighths  of  the  periphery  of 
the  ring. 

In  Fig.  292  one-half  of  one  revolution  of  the 
armature  is  completed,  and  the  resulting  mag- 


FIG.  292. 


FIG.  292A. 


netic  condition  of  the  ring  is  indicated  in  Fig. 
292A.  Now,  the  current  in  coil  C*is  nil,  while 
the  coil  C^  yields  its  maximum  current,  which 
is  of  the  same  direction  as  previously  ;  the 
magnetizing  effect  is,  therefore,  due  to  the  coils 
ct  cl  alone,  and,  referring  to  Fig.  292A,  it  will 
be  observed  that  the  poles  N  S  are  shifted  one- 


half  of  the  circumference  of  the  ring.  During 
the  next  half  revolution  the  operations  are 
repeated,  as  represented  in  the  Figs.  293  to 
295  A. 

A  reference  to  the  diagrams  will  make  it 
clear  that  during  one  revolution  of  the  arma- 
ture the  poles  of  the  ring  are  shifted  once 
around  its  periphery,  and  each  revolution  pro- 
ducing like  effects,  a  rapid  whirling  of  the 
poles  in  harmony  with  the  rotation  of  the 
armature  is  the  result.  If  the  connections  of 


FIG.  293.  FIG.  293 A. 

either  one  of  the  circuits  in  the  ring  are  re- 
versed, the  shifting  of  the  poles  is  made  to 
progress  in  the  opposite  direction,  but  the 
operation  is  identically  the  same.  Instead  of 
using  four  wires,  with  like  result,  three  wires 
may  be  used,  one  forming  a  common  return  for 
both  circuits. 

This  rotation  or  whirling  of  the  poles  mani- 
fests itself  in  a  series  of  curious  phenomena. 
If  a  delicately  pivoted  disc  of  steel  or  other 
magnetic- metal  is  approached  to  the  ring  it  is 
set  in  rapid  rotation,  the  direction  of  rotation 
varying  with  the  position  of  the  disc.  For  in- 


FIG.  294.  FIG.  294A. 

stance,  noting  the  direction  outside  of  the  ring 
it  will  be  found  that  inside  the  ring  it  turns  in 
an  opposite  direction,  while  it  is  unaffected  if 
placed  in  a  position  symmetrical  to  tin*  ring. 
This  is  easily  explained.  Each  time  that  a 
pole  approaches  it  induces  an  opposite  pole  in 
the  nearest  point  on  the  disc,  and  an  attraction 
is  produced  upon  that  point ;  owing  to  this,  as 
the  pole  is  shifted  further  away  from  the  disc 
a  tangential  pull  is  exerted  upon  the  same,  and, 
the  action  being  constantly  repeated,  a  more  or 


ALTERNATING  CURRENT  MOTORS. 


267 


less  rapid  rotation  of  the  disc  is  the  result.  As 
the  pull  is  exerted  mainly  upon-  that  part 
which  is  nearest  to  the  ring,  the  rotation  out- 
side and  inside,  or  right  and  left,  respectively, 
is  in  opposite  directions,  Fig.  287.  When 
placed  symmetrically  to  the  ring,  the  pull  on 
opposite  sides  of  the  disc  being  equal,  no  rota- 
tion results.  The  action  is  based  on  the  mag- 


FIG.  295. 


FIG.  295A. 


netic  inertia  of  the  iron  ;  for  this  reason  a  disc 
of  hard  steel  is  much  more  affected  than  a  disc 
of  soft  iron,  the  latter  being  capable  of  very 
rapid  variations  of  magnetism.  To  demonstrate 
the  complete  analogy  between  the  ring  and  a 
revolving  magnet,  a  strongly  energized  electro- 
magnet was  rotated  by  mechanical  power,  and 
phenomena  identical  in  every  particular  to 
those  mentioned  above  were  observed. 

Obviously,  the  rotation  of  the  poles  produces 
corresponding  inductive  effects,  and  may  be  u  til- 


o      o     o     o 

FIG.  296. 

ized  .to  generate  currents  in  a  closed  conductor 
placed  within  the  influence  of  the  poles.  For 
this  purpose  it  is  convenient  to  wind  a  ring  with 
two  sets  of  superimposed  coils  forming  respect- 
ively the  primary  and  secondary  circuits,  as 
Shown  in  Fig.  296.  In  order  to  secure  the  most 
economical  results  the  magnetic  circuit  should 
be  completely  closed,  and  with  this  object  in 
view  the  construction  may  be  modified  at  will. 


The  inductive  effect  exerted  upon  the  sec- 
ondary coils  will  be  mainly  due  to  the  shifting 
or  movement  of  the  magnetic  action  ;  but  there 
may  also  be  currents  set  up  in  the  circuits,  in 
consequence  of  the  variations  in  the  intensity 
of  the  poles.  However,  by  property  designing 
the  generator  and  determining  the  magnetizing 
effect  of  the  primary  coils,  the  latter  element 
may  be  made  to  disappear.  The  intensity  of 
the  poles  being  maintained  constant,  the  action 
of  the  apparatus  will  be  perfect,  and  the  same 
result  will  be  secured  as  though  the  shifting 
were  effected  by  means  of  a  commutator  with 
an  infinite  number  of  bars.  In  such  case  the 
theoretical  relation  between  the  energizing 
effect  of  each  set  of  primary  coils  and  their 
resultant  magnetizing  effect  may  be  expressed 
by  the  equation  of  a  circle  having  its  centre 
coinciding  with  that  of  an  orthogonal  system 


- — i \x— 


FIG.  297.  FIG-  298. 

of  axes,  and  in  which  the  radius  represents  the 
resultant  and  the  co-ordinates  both  of  its  com- 
ponents. These  are  then  respectively  the  sine 
and  cosine  of  the  angle  a  between  the  radius 
and  one  of  the  axes  (o  x}.  Referring  to  Fig. 
297,  we  have  r2  =  z3  +  y2  ;  where  x  —  r  cos  a, 
and  y  =  r  sin  «. 

Assuming  the  magnetizing  effect  of  each  set 
of  coils  in  the  transformer  to  be  proportioned 
to  the  current — which  may  be  admitted  for 
weak  degrees  of  magnetization — then  x  =  K  c 
and  ?/  =  K  c1.  where  Kis  a  constant  and  c  and 


c1  the  current  in  both  sets  of  coils  respectively. 
Supposing,  further,  the  field  of  the  generator 
to  be  uniform,  we  have  for  constant  speed  c1  = 
Kl  sin  «,  and  c  =  Kl  sin  (90°  +  «)  —  K*  cos  «, 
where  Kl  is  a  constant.  See  Fig.  298. 

Therefore,    x  —  K  c  =  K  Kl  cos  «  ; 

y-Kcl  =  K K1  sin  «,  and 
' 


268 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


That  is,  for  a  uniform  field  the  disposition 
of  the  two  coils  at  right  angles  will  secure  the 
theoretical  result,  and  the  intensity  of  the 
shifting  poles  will  be  constant.  But  from 
r3=x2+y2  it  follows  that  fory  —  O,  r  =  x\  it 
follows  that  the  joint  magnetizing  effect  of 
both  sets  of  coils  should  be  equal  to  the  effect 
of  one  set  when  at  its  maximum  action.  In 
transformers  and  in  a  certain  class  of  motors 
the  fluctuation  of  the  poles  is  not  of  great  im- 
portance, but  in  another  class  of  these  motors 
it  is  desirable  to  obtain  the  theoretical  result. 

In  applying  this  principle  to  the  construction 
of  motors,  two  typical  forms  of  machines  have 
been  developed  by  Mr.  Tesla.  First,  a  form 
having  a  comparatively  small  rotary  effort  at 
the  start,  but  maintaining  a  perfectly  uniform 
speed  at  all  loads,  which  motor  has  been  termed 
synchronous.  Second,  a  form  possessing  a 
great  rotary  effort  at  the  start,  the  speed  being 
dependent  on  the  load. 

These  motors  may  be  operated  in  three  dif- 
ferent ways :  (1)  By  the  alternate  currents  of 
the  source  only  ;  (2)  by  a  combined  action  of 
these  and  of  induced  currents  ;  (3)  by  the  joint 
action  of  alternate  and  continuous  currents. 

The  simplest  form  of  a  synchronous  motor  is 
obtained  by  winding  a  laminated  ring  provided 
with  pole  projections  with  four  coils,  and  con- 
necting the  same  in  the  manner  before  indi- 
cated. An  iron  disc  having  a  segment  cut  away 
on  each  side  may  be  used  as  an  armature. 
Sucli  a  motor  is  shown  in  Fig.  287.  The  disc 
being  arranged  to  rotate  freely  within  the  ring 
in  close  proximity  to  the  projections,  it  is 
evident  that,  as  the  poles  are  shifted,  it  will, 
owing  to  its  tendency  to  place  itself  in  such  a 
position  as  to  embrace  the  greatest  number  of 
the  lines  of  force,  closely  follow  the  movement 
of  the  poles,  and  its  motion  will  be  synchron- 
ous with  that  of  the  armature  of  the  generator ; 
that  is,  in  the  peculiar  disposition  shown  in 
Fig.  287,  in  which  the  armature  produces  by 
one  revolution  two  current  impulses  in  each  of 
the  circuits.  It  is  evident  that  if,  by  one  revo- 
lution of  the  armature,  a  greater  number  of 
impulses  is  produced,  the  speed  of  the  motor 
will  be  correspondingly  increased.  Consider- 
ing that  the  attraction  exerted  upon  the  disc  is 
greatest  when  the  same  is  in  close  proximity 


to  the  poles,  it  follows  that  such  a  motor  will 
maintain  exactly  the  same  speed  at  all  loads 
within  the  limits  of  its  capacity. 

To  facilitate  tlie  starting,  the  disc  may  be 
provided  with  a  coil  closed  upon  itself.  The 
advantage  secured  by  such  a  coil  is  evident. 
On  the  start  the  currents  set  up  in  the  coil 
strongly  energize  the  disc,  and  increase  the 
attraction  exerted  upon  the  same  by  the  ring, 
and  currents  being  generated  in  the  coil  as  long 
as  the  speed  of  the  armature  is  inferior  to  that 
of  the  poles  ;  considerable  work  may  be  per- 
formed by  such  a  motor,  even  if  the  speed  be 
below  normal.  The  intensity  of  the  poles  be- 
ing constant,  no  currents  will  be  generated  in 
the  coil  when  the  motor  is  turning  at  its  normal 
speed. 

Instead  of  closing  the  coil  upon  itself,  its 
ends  may  be  connected  to  two  insulated  sliding 
rings,  and  a  continuous  current  supplied  to 
these  from  a  suitable  generator.  The  proper 
way  to  start  such  a  motor  is  to  close  the  coil 
upon  itself  until  the  normal  speed  is  reached, 
or  nearly  so,  and  then  turn  on  the  continuous 
current.  If  the  disc  be  very  strongly  energized 
by  a  continuous  current  motor  it  may  not  be 
able  to  start,  but  if  it  be  weakly  energized,  or 
generally  so  that  the  magnetizing  effect  of  the 
ring  is  preponderating,  it  will  start  and  reach 
the  normal  speed.  Such  a  motor  will  maintain 
absolutely  the  same  speed  at  all  loads.  It  has 
also  been  found  that  if  the  motive  power  of 
the  generator  is  not  excessive,  by  checking  the 
motor  the  speed  of  the  generator  is  diminished 
in  synchronism  with  that  of  the  motor.  It  is 
characteristic  of  this  form  of  motor  that  it  can- 
not be  reversed  by  reversing  the  continuous 
current  through  the  coil. 

The  synchronism  of  these  motors  may  be 
demonstrated  experimentally  in  a  variety  of 
ways.  For  this  purpose  it  is  best  to  employ  a 
motor  consisting  of  a  stationary  field  magnet 
and  an  armature  arranged  to  rotate  within  the 
same,  as  indicated  in  Fig.  299.  In  this  case 
the  shifting  of  the  poles  of  the  armature  pro- 
duces a  rotation  of  the  latter  in  the  opposite 
direction.  It  results  therefrom  that  when  the 
normal  speed  is  reached,  the  poles  of  the  arma- 
ture assume  fixed  positions  relatively  to  the 
field  magnet,  and  the  same  is  magnetized  by 


ALTERNATING   CURRENT   MOTORS. 


260 


induction,  exhibiting  a  distinct  pole  on  each 
of  the  pole-pieces.  If  a  piece  of  soft  iron  is 
approached  to  the  field  magnet  it  will  at  the 
start  be  attracted  with  a  rapid  vibrating  motion 
produced  by  the  reversals  of  polarity  of  the 
magnet,  but  as  the  speed  of  the  armature  in- 
the  vibrations  become  less  and  less 


*B 

creases 


FIG.  299. 

frequent  and  finally  entirely  cease.  Then  the 
iron  is  weakly  but  permanently  attracted,  show- 
ing that  synchronism  is  reached  and  the  field 
magnet  energized  by  induction. 

The  disc  may  also  be  used  for  the  experi- 
ment. If  held  quite  close  to  the  armature,  it- 
will  turn  as  long  as  the  speed  of  rotation  of  the 
poles  exceeds  that  of  the  armature  ;  but  when 
the  normal  speed  is  reached,  or  very  nearly  so, 
it  ceases  to  rotate  and  is  permanently  attracted. 

In  motors  of  the  synchronous  type  it  is  de- 
sirable to  maintain  the  quantity  of  the  shifting 
magnetism  constant,  especially  if  the  magnets 
are  not  properly  subdivided. 

To  obtain  a  rotary  effort  in  these  motors,  it 
was  necessary  to  make  such  a  disposition  that 
while  the  poles  of  one  element  of  the  motor  are 
shifted  by  the  alternate  currents  of  the  source, 
the  poles  produced  upon  the  other  element 
should  always  be  maintained  in  the  proper  re- 
lation to  the  former,  irrespective  of  the  speed  of 
the  motor.  Such  a  condition  exists  in  a  contin- 
uous-current motor  ;  but  in  a  synchronous  mo- 
tor, such  as  described,  this  condition  is  fulfilled 
only  when  the  speed  is  normal. 

The  object  has  been  attained  by  placing 
within  the  ring  a  properly  subdivided  cylin- 
drical iron  core  wound  with  several  independ- 


ent coils  closed  upon  themselves.  Two  coils 
at  right  angles,  as  in  Fig.  300,  are  sufficient, 
but  a  greater  number  may  be  advantageously 
employed.  It  results  from  this  disposition 
that  when  the  poles  of  the  ring  are  shifted, 
currents  are  generated  in  the  closed  armature 
coils.  These  currents  are  the  most  intense  at 
or  near  the  points  of  the  greatest  density  of 
the  lines  of  force,  and  their  effect  is  to  produce 
poles  upon  the  armature  at  right  angles  to 
those  of  the  ring,  at  least  theoretically  so;  and 
since  this  action  is  entirely  independent  of  the 
speed — that  is,  so  far  as  the  location  of  the 
poles  is  concerned — a  continuous  pull  is  exerted 
upon  the  periphery  of  the  armature.  In  many 
respects  these  motors  are  similar  to  the  con- 
tinuous-current motors.  If  load  is  put  on,  the 
speed,  and  also  the  resistance  of  the  motor,  is 
diminished  and  more  current  is  made  to  pass 
through  the  energizing  coils,  thus  increasing 
the  effort.  Upon  the  load  being  taken  off,  the 
counter-electromotive  force  increases  and  less 
current  passes  through  the  primary  or  ener- 
gizing coils.  Without  any  load  the  speed  is 
very  near!  y  equal  to  that  of  the  shifting  poles 
of  the  field  magnet. 

According  to  Mr.  Tesla,  the  rotary  effort  in 
these  motors  fully  equals  that  of  the  continu- 
ous current  motors.  The  effort  seems  to  be 


FIG.  300. 

greatest  when  both  armature  and  field  magnets 
are  without  any  projections ;  but  as  in  such 
dispositions  the  field  cannot  be  very  concen- 
trated, probably  the  best  results  will  be  ob- 
tained by  leaving  pole  projections  on  one  of 
the  elements  only.  Generally,  it  may  be  stated 
that  the  projections  diminish  the  torque  and 
produce  a  tendency  to  synchronism. 


270 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


A  characteristic  feature  of  motors  of  this 
kind  is  their  capacity  of  being  very  rapidly  re- 
versed. This  follows  from  the  peculiar  action 
of  the  motor.  Suppose  the  armature  to  be 
rotating,  and  the  direction  of  rotation  of  the 
poles  to  be  reversed.  The  apparatus  then 
represents  a  dynamo  machine,  the  power  to 
drive  this  machine  being  the  momentum  stored 
up  in  the  armature,  and  its  speed  being  the  sum 
of  the  speeds  of  the  armature  and  the  poles. 
If  we  now  consider  that  the  power  to  drive 
such  a  dynamo  would  be  very  nearly  propor- 
tional to  the  third  power  of  the  speed,  for  this 
reason  alone  the  armature  should  be  quickly 
reversed.  But  simultaneously  with  the  re- 
versal another  element  is  brought  into  action, 
namely,  as  the  movement  of  the  poles  with 
respect  to  the  armature  is  reversed,  the  motor 
acts  like  a  transformer  in  which  the  resistance 
of  the  secondary  circuit  would  be  abnormally 
diminished,  by  producing  in  this  circuit  an 
additional  electromotive  force.  Owing  to  these 
causes  the  reversal  is  instantaneous. 

If  it  is  desirable  to  secure  a  constant  speed, 
and  at  the  same  time  a  certain  effort  at  the 
start,  this  result  may  be  easily  attained  in  a 
variety  of  ways.  For  instance,  two  armatures, 
one  for  torque  and  the  other  for  synchronism, 
may  be  fastened  on  the  same  shaft,  and  any 
desired  preponderance  may  be  given  to  either 
one  ;  or  an  armature  may  be  wound  for  rotary 
effort,  but  a  more  or  less  pronounced  tendency 
to  synchronism  may  be  given  to  it  by  properly 
constructing  the  iron  core  ;  and  in  many  other 
ways. 

As  a  means  of  obtaining  the  required  phase 
of  the  currents  in  both  the  circuits,  the  dispo- 
sition of  the  two  coils  at  right  angles  is  the 
simplest,  securing  the  most  uniform  action ; 
but  the  phase  may  be  obtained  in  many  other 
ways,  varying  with  the  machine  employed. 
Any  of  the  dynamos  at  present  in  use  may  be 
easily  adapted  for  this  purpose  by  making 
connections  to  proper  points  of  the  generating 
coils.  In  closed  circuit  armatures,  such  as  used 
in  the  continuous-current  systems,  it  is  best  to 
make  four  derivations  from  equi-distant  points 
or  bars  of  the  commutator,  and  to  connect  the 
same  to  four  insulated  sliding  rings  on  the 
shaft.  In  this  case  each  of  the  motor  circuits 


is  connected  to  two  diametrically  opposite  bars 
of  the  commutator.  In  such  a  disposition  the 
motor  may  also  be  operated  at  half  the  poten- 
tial and  on  the  three-wire  plan,  by  connecting 
the  motor  circuits  in  the  proper  order  to  three 
of  the  contact-rings. 

In  multipolar  dynamo  machines,  such  as 
used  in  the  converter  systems,  the  phase  is 
conveniently  obtained  by  winding  upon  the 
armature  two  series  of  coils  in  such  a  manner 
that  while  the  coils  of  one  set  or  series  are  at 
their  maximum  production  of  current,  the 
coils  of  the  other  will  be  at  their  neutral  posi- 
tion, or  nearly  so  ;  whereby  both  sets  of  coils 
may  be  subjected  simultaneously  or  success- 
ively to  the  inducing  action  of  the  field  mag- 
nets. 

Generally,  the  circuits  in  the  motor  will  be 
similarly  disposed,  and  various  arrangements 
may  be  made  to  fulfill  the  requirements  ;  but 
the  simplest  and  most  practicable  is  to  arrange 


X 


FIG.  301. 


FIG.  302. 


FIG.  303. 


primary  circuits  on  stationary  parts  of  the 
motor,  thereby  obviating,  at  least  in  certain 
forms,  the  employment  of  sliding  contacts. 
In  such  a  case  the  magnet  coils  are  connected 
alternately  in  both  the  circuits  ;  that  is,  1,  3,  5 
...  .in  one,  and  2,  4,  6 ....  in  the  other,  and  the 
coils  of  each  set  of  series  may  be  connected  all 
in  the  same  manner,  or  alternately  in  opposi- 
tion ;  in  the  latter  case,  a  motor  with  half  the 
number  of  poles  will  result,  and  its  action  will 
be  correspondingly  modified.  The  diagrams, 
Pigs.  301,  302  and  303,  show  three  different 
phases,  the  magnet  coils  in  each  circuit  being 
connected  alternately  in  opposition.  In  this 
case  there  will  always  be  four  poles,  as  in 
Figs.  301  and  302,  four  pole  projections  being 
neutral,  and  in  Fig.  303  two  adjacent  pole  pro- 
jections will  have  the  same  polarity.  If:  the 
coils  are  connected  in  the  same  manner  there 
will  be  eight  alternating  poles,  as  indicated  by 
the  letters  ri  s'  in  Fig.  301. 


ALTERNATING  CURRENT   MOTORS. 


271 


The  employment  of  multipolar  motors  se- 
cures in  this  system  an  advantage  much  desired, 
and  that  is,  that  a  motor  may  be  made  to  run 
exactly  at  a  predetermined  speed,  irrespective 
of  imperfections  in  construction,  of  the  load, 
and,  within  certain  limits,  of  electromotive 
force  and  current  strength. 

In  a  general  distribution  system  of  this  kind, 
according  to  Mr.  Tesla,  the  following  plan 
should  be  adopted  :  At  the  central  station  of 
supply  a  generator  should  be  provided,  having 
a-  considerable  number  of  poles.  The  motors 
operated  from  this  generator  should  be  of  the 
synchronous  type,  but  possessing  sufficient 
rotary  effort  to  insure  their  starting.  With 
the  observance  of  proper  rules  of  construction, 
it  may  be  admitted  that  the  speed  of  each 
motor  will  be  in  some  inverse  proportion  to  its 
size,  and  the  number  of  poles  should  be  chosen 
accordingly.  Still,  exceptional  demands  may 
modify  this  rule.  In  view  of  this,  it  may  be 
advantageous  to  provide  each  motor  with  a 
greater  number  of  pole  projections  or  coils,  the 
number  being  preferably  a  multiple  of  two  and 
three.  By  this  means,  by  simply  changing  the 
connections  of  the  coils,  the  motor  may  be 
adapted  to  any  probable  demands. 

If  the  number  of  the  poles  in  the  motor  is 
even,  the  action  will  be  harmonious,  and  the 
proper  result  will  be  obtained  ;  if  this  is  not 
the  case,  the  best  plan  to  be  followed  is  to  make 
a  motor  with  a  double  number  of  poles  and 
connect  the  same  in  the  manner  before  indi- 
cated, so  that  half  the  number  of  poles  result. 
Suppose,  for  instance,  that  the  generator  has 
twelve  poles,  and  it  would  be  desired  to  obtain 
a  speed  equal  to  \?  of  the  speed  of  the  genera- 
tor. This  would  require  a  motor  with  seven  pole 
projections  or  magnets,  and  such  a  motor  could 
not  be  properly  connected  in  the  circuits  unless 
fourteen  armature  coils  would  be  provided, 
which  would  necessitate  the  employment  of  slid- 
ing contacts.  To  avoid  this  the  motor  should  be 
provided  with  fourteen  magnets,  and  seven  con- 
nected in  each  circuit,  the  magnets  in  each  cir- 
cuit alternating  among  themselves.  The  arma- 
ture should  have  fourteen  closed  coils.  The 
action  of  the  motor  will  not  be  quite  as  perfect 
as  in  the  case  of  an  even  number  of  poles,  but 
the  drawback  will  not  be  of  a  serious  nature. 


However,  the  disadvantages  resulting  from 
this  unsymmetrical  form  will  be  reduced  in  the 
same  proportion  as  the  number  of  the  poles  is 
augmented.  If  the  generator  has,  say,  n, 
and  the  motor  nl  poles,  the  speed  of  the  motor 
will  be  equal  to  that  of  the  generator  multi- 

T) 

plied  by  -' 

The  speed  of  the  motor  will  generally  be  de- 
pendent on  the  number  of  the  poles,  but  there 
may  be  exceptions  to  this  rule.  The  speed  may 
be  modified  by  the  phase  of  the  currents  in  the 
circuits,  or  by  the  character  of  the  current  im- 
pulses, or  by  the  intervals  between  each,  or 
between  groups  of  impulses.  Some  of  the 
possible  cases  are  indicated  in  the  diagrams, 
Figs.  304,  305,  306  and  307,  which  are  self- 
explanatory.  Fig.  304  represents  the  con- 
dition generally  existing,  and  which  secures 
the  best  result.  In  such  a  case,  if  the  typical 
form  of  motor  illustrated  in  Fig.  287  is  em- 


FIG.  304.        Fm.  305.       FIG.  306.      FIG.  307. 

ployed,  one  complete  wave  in  each  circuit  will 
produce  one  revolution  of  the  motor.  In  Fig. 
305  the  same  result  will  be  effected  by  one  wave 
in  each  circuit,  the  impulses  being  successive  ; 
in  Fig.  306  by  four,  and  in  Fig.  307  by  eight 
waves. 

By  such  means  any  desired  speed  may  be 
attained  ;  that  is,  at  least  within  the  limits  of 
practical  demands.  This  system  possesses  this 
advantage  besides  others,  resulting  from  sim- 
plicity. At  full  loads,  according  to  Mr.  Tesla, 
the  motors  show  an  efficiency  fully  equal  to 
that  of  the  continuous  current  motors.  The 
transformers  present  an  additional  advantage 
in  their  capability  of  operating  motors. 

We  may  add  that  shortly  after  the  publi- 
cation of  Mr.  Tesla' s  work.  Professor  Galileo 
Ferraris,  of  Turin,  Italy,  published  as  the  re- 
sult of  independent  study  an  essay,  in  which, 
under  the  title  of  "  Electro-Dynamic  Rotation," 
he  described  phenomena  similar  to  those  already 
employed  by  Mr.  Tesla  in  his  motors. 


CHAPTER    XVI. 


THERMO-VIAQNETIC    MOTORS. 


WHILE  the  class  of  motors  described  in  the 
last  chapter  occupies  the  attention  of  many 
electricians  at  the  present  time,  still  another 
type,  depending  upon  an  entirely  different  prin- 
ciple, has  recently  come  into  prominence,  and 
although  such  motel's  are  still  largely  in  an 
experimental  stage  their  possible  future  prac- 
ticability, as  well  as  their  theoretical  interest, 
makes  some  mention  of  them  in  this  work 
necessary. 

These  motors,  which  may  be  termed  "  thermo- 
magnetic,"  are  based  upon  a  principle  which 
has  long  been  known,  and  which,  indeed,  was 
first  announced  by  that  pioneer  in  electricity 
and  magnetism,  Dr.  William  Gilbert.  He  first 
showed  that  when  a  loadstone  or  iron  bar  was 
heated  to  redness  it  lost  its  magnetism.  Since 
then  the  influence  of  heat  on  magnetic  metals, 
such  as  iron,  nickel,  cobalt,  etc.,  has  been  well 
recognized,  and  the  experiment  has  often  been 
made,  showing  that  a  soft  iron  armature 
strongly  attracted  by  an  electro-magnet  when 
cold,  is  easily  withdrawn  when  the  armature  is 
heated  to  redness.  The  explanation  of  this 
phenomenon  is  referred  to  the  fact  that  at  red 
heat  the  molecules  of  iron  lose  their  coercitive 
force  and  the  iron  becomes  magnetically  inert, 
exhibiting  no  greater  magnetic  properties  than 
other  metals. 

Although,  as  stated,  these  phenomena  have 
long  been  known,  they  were  not  for  a  long  time 
applied  to  the  construction  of  machines  either 
for  the  generation  of  electricity  or  the  conver- 
sion of  heat  into  mechanical  work  through  the 
medium  of  magnetism.  Among  the  first  to 
undertake  experiments  in  this  direction  was 
Dr.  G.  Gore,  who  in  1868  succeeded  in  generat- 
ing a  current  by  the  heating  and  cooling  of  a 
magnet  placed  in  inductive  proximity  to  a  coil 
of  wire. 


Dr.  Gore's  apparatus*  consisted  of  a  coil  of 
wire  through  the  hollow  of  which  passed  an 
iron  wire  1.03  mm.  in  diameter.  This  iron 
wire  was  kept  magnetized  by  contact  witli  the 
ends  of  a  permanent  magnet  which  passed 
around  the  outside  of  the  coil,  and  the  arrange- 
ment was  such  that  the  iron  wire  forming  the 
core  of  the  helix  could  be  heated  by  the  pas- 
sage of  an  electric  current  from  a  battery.  The 
helix  being  connected  with  a  galvanometer  the 
current  was  alternately  made  and  broken 
through  the  iron  wire,  causing  alternate  heat- 
ing and  cooling  and  a  corresponding  change  in 
its  magnetic  strength.  This  variation  in  mag- 
netism acting  on  the  surrounding  helix  caused 
the  generation  of  induced  currents  in  the  well- 
known  manner,  which  currents  were  made 
manifest  in  the  galvanometer. 

In  a  subsequent  paper,  Dr.  Oliver  Lodge 
showed  the  influence  of  heat  upon  the  action 
of  two  spirals,  one  of  magnetic  and  the  other 
of  non-magnetic  metal,  placed  in  proximity  to 
a  magnetic  needle,  t 

These  experiments,  though  crude,  neverthe- 
less gave  some  clue  to  the  methods  to  be 
employed  ;  the  latter  experiment  especially  in- 
dicating a  means  of  obtaining  motion  through 
the  medium  of  magnetism  and  heat. 

While  engaged  in  investigations  concerning 
the  increase  in  the  coercitive  force  of  steel 
by  changes  of  temperature,  Professors  Elihu 
Thomson  and  E.  J.  Houston,  in  1878,  devised 
an  elementary  form  of  thermo-magnetic  motor,:}: 
shown  in  the  illustration,  Fig.  308. 

*  For  a  full  description,  see  Dr.  Gore's  paper,  "  On  the  Devel- 
opment of  Electric  Currents  by  Magnetism  and  Heat."  Proc. 
Roy.  Soe.,  Vol.  XVIL,  1868-1869,  p.  261.  Also,  Phil.  Mag., 
Vol.  XXXVIII..  1869,  p.  60. 

fSee  Phil.  Mag.,  Vol.  XL.,  1870,  p.  170,  "On  the  Mag- 
netism of  Electro-Dynamic  Spirals." 

t  See  Journ.  Franklin  Inel.,  1879,  p.  39. 


THERMO-MAGNETIC   MOTORS 


273 


As  will  be  seen,  a  disc  or  ring  of  thin  steel 
D  is  mounted  on  an  axis,  so  as  to  be  quite  free 
to  move.  The  edges  of  the  wheel  are  placed 
opposite  the  poles  N  and  >&'of  a  magnet,  and 
in  this  position  the  wheel  of  course  becomes 
magnetized  by  induction.  If,  now,  any  section 
of  the  wheel,  as  //,  be  sufficiently  heated,  the 
disc  will  move  in  the  direction  shown  by  the 
arrow.  The  cause  of  the  motion  is  as  follows  : 


FIG.  308. — EXPERIMENTAL  PYROMAGNETIC  MOTOR. 

The  section  H,  when  heated,  has  its  coercitive 
force  increased  thereby,  and,  being  less  power- 
fully magnetized  by  the  induction  of  the  pole 
S  than  the  portion  C  immediately  adjacent  to 
it,  the  attraction  exerted  by  the  pole  S  on  the 
latter  portion  is  thereby  sufficient  to  cause  a 
movement  of  the  disc  in  the  direction  shown 
by  the  arrow.  If  a  constant  source  of  heat  be 
placed  at  ff,  a  slow  rotation  in  the  direction 
shown  is  maintained. 

To  insure  success,  the  steel  disc  must  be  suf- 
ficiently thin  to  prevent  its  acquiring  a  tiniform 
temperature.  If  the  source  of  heat  be  at  the 
same  time  applied  at  diametrically  opposite 
portions  of  the  disc,  as  at  //and  D,  adjacent 
to  the  poles,  the  same  effect  will  be  produced. 
The  experimenters  remark  truly  that  since  the 
amount  of  heat  expended  in  producing  motion 
of  the  disc  is  so  enormous  when  compared  with 
the  force  developed,  it  will  be  readily  under- 
stood that  this  motor  is  of  no  value  as  such, 
but  must  be  regarded  as  an  interesting  example 
of  the  interconvertibility  of  force. 

A  somewhat  similar  experiment  was  described 
by  C.  K.  McGee  in  1884,*  and  is  illustrated  in 
Fig.  309. 

*  Science,  March  7,  1884,  p.  274. 


Here  a  b  c  represents  a  ring  thirteen  centi- 
metres in  diameter,  and  supported  horizontally 
upon  radial  arms  and  an  axis  of  some  non- 
magnetic metal.  This  ring  was  made  of  one  or 
more  turns  of  iron  wire  of  about  a  millimetre 
diameter,  and  N  8  was  either  a  permanent  or 
an  electro-magnet.  The  axis  was  furnished 
with  a  driving  pulley,  cord  and  weight,  as 
shown  in  the  figure. 

That  part  of  the  ring  which  lay  between  a 
and  c  was  heated  to  bright  redness  by  means  of 
two  or  three  Bunsen  burners.  The  magnet 
then  exerted  a  preponderating  attraction  upon 
the  farther  or  cool  side  of  the  ring,  and  the 
latter  revolved  as  indicated  by  the  arrow.  As 
fast  as  the  ring  entered  the  space  a  b  c,  it  be- 
came red  hot  and  non-magnetic,  and  a  lack  of 
equilibrium  was  thus  maintained  which  re- 
sulted in  a  continuous  rotation. 

The  motion  was  necessarily  quite  slow,  on 
account  of  the  considerable  time  required  to 
heat  the  iron  ring.  In  the  actual  experiment, 
considerable  difficulty  was  experienced  from 
the  distortion  which  the  ring  underwent  when 
softened  by  the  heat,  in  consequence  of  which 
the  speed  of  rotation  became  very  irregular. 
With  a  permanent  steel  magnet  a  speed  of 


/w\ 

FIG.  309.— McGEE's  MOTOR. 
about  one  revolution  in  two  minutes  was  ob- 
tained ;  and  with  a  powerful  electro-magnet  a 
weight  of  six  grams  was  raised  fifty  centi- 
metres in  six  minutes ;  and,  in  a  second 
experiment  (the  ring  having  become  quite  dis- 
torted), ninety  centimetres  in  thirty  minutes. 

Still  another  experiment  recorded, of  a  similar 
character,  is  that  of  Schwedoff.  As  shown  in 
the  accompanying  illustration,  Fig.  310,  an  iron 


274 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


ring  is  provided  with  four  brass  spokes,  by 
which  it  is  pivoted  at  the  centre  so  as  to  be  free 
to  rotate  in  its  own  plane.  A  steel  magnet  is 
brought  near  one  side,  and  at  a  distance  of 
about  45°  a  Bunsen  burner  is  placed.  The 
magnetic  permeability  of  the  iron  being  greatly 
weakened  by  the  heat  from  the  flame,  the  effect 
is  the  same  as  if  this  part  of  the  ring  were 
made  of  brass  or  some  other  non-magnetic 
material ;  consequently  the  magnet  tends  to 
pull  the  ring  round  in  the  direction  of  the 
arrow,  so  as  to  restore  the  symmetry  of  the 
field.  But  as  the  hot  part  rapidly  cools  when 
removed  from  the  flame,  and  the  adjacent 
section  is  heated,  the  distribution  of  tempera- 
ture, and  therefore  of  magnetic  permeability, 
remains  fixed  in  space,  and  a  continuous 
rotation  is  therefore  set  up. 

These  experiments,  however,  attracted  but 
little  notice,  and  it  was  not  until  recently  that 
general  attention  was  arrested  on  the  subject, 


FIG.  310. — SCHVVEDOFF'S  THERMO-MAGNETIC  MOTOR. 
bv  a  paper  read  by  Mr.  Thomas  A.  Edison, 
before  the  American  Association  for  the  Ad- 
vancement of  Science,  in  August,  1887.*  Mr. 
Edison  introduced  an  adjunct  in  his  "pyro 
magnetic  motor,"  in  the  shape  of  a  refrigerator 
or  cooling  arrangement,  which  greatly  increases 
the  efficiency  of  the  apparatus,  and  his  machine 
included  a  better  arrangement  for  obtaining 
the  maximum  effect  due  to  the  magnetic  action. 
In  order  to  explain  the  action  of  this  interest- 
ing motor,  let  us  suppose  a  permanent  magnet 
having  a  bundle  of  small  tubes  made  of  thin 
iron  placed  between  its  poles  and  capable  of 
rotation  about  an  axis  perpendicular  to  the 
plane  of  the  magnet  after  the  fashion  of  an 
armature.  Suppose  further,  that  by  suitable 

*  See  The  Electrical  World,  August  27,  1887. 


means,  such  as  a  blast  or  a  draught,  hot  air  can 
be  made  to  pass  through  these  tubes  so  as  to 
raise  them  to  redness,  and  that  by  a  flat  screen 
symmetrically  placed  across  the  face  of  this 
bundle  of  tubes,  and  covering  one-half  of  them, 
access  of  the  heated  air  to  the  tubes  beneath  it 
is  prevented.  Then  it  follows  that  if  this 
screen  be  so  adjusted  that  its  ends  are  equi- 
distant from  the  two  legs  of  the  magnet,  the 
bundle  of  tubes  will  not  rotate  about  the  axis, 
since  the  cooler  and  magnetic  portions  of  the 
tube-bundle  (i.  e.,  those  beneath  the  screen)  will 
be  equidistant  from  the  poles  and  will  be 
equally  attracted  on  the  two  sides.  But  if  the 
screen  be  turned  about  the  axis  of  rotation 
so  that  one  of  its  ends  be  nearer  one  of  the 
poles  and  the  other  nearer  the  other,  then 
rotation  of  the  bundle  will  ensue,  since  the 
portion  under  the  screen,  which  is  cooler,  and 
therefore  magnetizable,  is  continually  more 
strongly  attracted  than  the  other  and  heated 
portion.  This  device  acts,  therefore,  as  a  mag- 
netic thermo-motor,  the  heat  now  passing 
through  the  tubes  in  such  a  way  as  to  produce 
a  dissymmetry  in  the  lines  of  force  in  the  iron 
field,  the  rotation  being  due  to  the  effort  to 
make  these  symmetrical.  The  guard-plate  in 
this  case  has  an  action  analogous  to  that  of  the 
commutator  in  an  ordinary  armature.  The  first 
experimental  motor  constructed  on  this  princi- 
ple was  heated  by  means  of  two  small  Bunsen 
burners,  arranged  with  an  air  blast,  and  it  de- 
veloped about  700  foot-pounds  per  minute. 

A  second  and  larger  motor  embodying  these 
principles  has  also  been  constructed,  weighing 
about  1,500  pounds  and  calculated  to  develop 
about  3  horse-power.  This  machine  is  shown 
in  diagrammatic  perspective  and  in  section, 
respectively,  in  Figs.  311  and  312.  As  will  be 
seen,  the  armature  placed  between  the  poles  of 
an  electro-magnet  consists  of  a  bundle  of  small 
iron  tubes  TT,5r7  of  an  inch  thick.  The  armature 
is  fixed  to  a  hollow  upright  rod  Ji,  through 
which  a  blast  of  cool  air  is  brought  to  the 
machine.  The  cool  air  issuing  through  the 
openings  at  a  enters  the  screen  S,  and  is  directed 
downward  through  the  tubes  directly  under 
the  screen,  as  shown  by  the  arrows.  At  the 
bottom  of  the  armature  it  meets  a  similar  screen 
8',  which  forces  the  air  back  into  the  tube  Ji 


THERMO-MAGNETIC   MOTORS. 


275 


through  the  openings  at  o.  The  air  then  passes 
down  the  tube  and  passes  out  of  the  openings 
d  d  under  the  lire,  acting  as  a  draught  for  the 
same.  Continuing  on  as  hot  furnace  gases,  it 
passes  up  through  the  armature  tubes,  which 
are  not  screened,  heating  them  up,  and  finally 
passing  out  at  the  chimney  c. 


Fi<;.  311. — EDISON'S  PYROMAGNETIC  MOTOR. 

Now,  since  the  screens  S  Sl  are  placed  un- 
symmetrically,  and  from  what  has  been  said  be- 
fore, it  follows  that  the  cool  tubes  between  the 
screens  will  be  magnetic,  while  the  tubes  heated 
by  the  furnace  gases  will  be  non-magnetic.  The 
result  is  that  an  attraction  will  take  place  be- 
tween the  magnetic  tubes  and  the  pole-pieces 
of  the  electro-magnet,  caiising  a  rotation.  This 
rotation  is  maintained  continuously  by  the 
blast  of  cool  air,  which  converts  the  inert  mag- 
netic iron  into  magnetic  as  soon  as  it  comes 
under  the  screen,  the  cooled  portion  remaining 
iixcd  in  space  while  the  armature  revolves. 

Like  all  heat-engines,  the  efficiency  of  this 
motor,  other  things  being  equal,  will  depend 
upon  the  temperature  difference  in  working,  the 
rate  of  temperature  variation,  and  upon  the 
proximity  to  the  points  of  maximum  magnetic 
effect.  No  advantage  will  be  gained,  of  course, 
by  raising  the  temperature  of  the  heated  por- 


tion of  the  armature  above  the  point  at  which 
its  magnetizability  is  practically  zero ;  nor,  on 
the  other  hand,  would  it  be  advantageous  to 
cool  the  part  between  the  screens  below  the 
point  where  its  magnetic  strength  is  practically 
a  maximum.  The  points  of  temperature,  there- 
fore, between  which  for  any  given  magnetic 
metal  it  is  most  desirable  to  work,  can  be  easily 
determined  by  an  inspection  of  the  curve  show- 
ing the  relations  between  heat  and  magnetism 
for  this  particular  metal.  Thus  the  points  of 
temperature  at  which  the  magnetizability  is 
practically  zero,  as  above  stated,  are  a  white 
heat  for  cobalt,  a  bright  red  for  iron,  and  400°  C. 
for  nickel.  On  the  other  hand,  while,  accord- 
ing to  Prof.  Rowland,*  at  ordinary  tempera- 
tures iron  has  a  maximum  intensity  of  magnet- 
ization represented  by  1,390,  its  intensity  at 


FIG.  312. — EDISON'S  PYROMAGNETIC  MOTOR. 

220°  C.  is  1,360,  and  hence  no  practical  advan- 
tage is  gained  by  cooling  the  iron  below  this 
temperature.  Nickel,  however,  whose  maxi- 
mum intensity  of  magnetization  at  ordinary 
temperature  is  494,  has  an  intensity  of  only  380 
at  220°  C.  Hence,  while  this  metal  requires  a 
lower  maximum  temperature,  it  also  requires  a 
*5>ee  Phil.  May.,  1873,  Vol.  XLVL,  [>.  157,  and  Nov.,  1874. 


276 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


lower  minimum  one ;  but  it  may  be  worked 
with  much  less  heat. 

In  the  paper  referred  to  above,  Mr.  Edison 
:ilso described  a pyromagnetic  dynamo,'"  which, 
though  based  on  the  same  principle,  differed 
somewhat  in  construction  from  the  motor. 
We  mention  it  here, however,  on  account  of  the 
close  connection  between  the  two,  nnd  the  ready 
convertibility  of  the  dynamo  into  a  motor. 


FIG.  313. — MENGES'  PYROMAGNETIC   GENERATOR- 
MOTOR. 

A  dynamo  and  a  motor  analogous  in  prin- 
ciple to  those  of  Mr.  Edison  have  also  been 
designed  by  M.  Menges,  of  the  Hague,  Hol- 
land. In  this  motor  the  inventor  has  tried  to 
overcome  the  difficulty  encountered  in  the 
heating  and  cooling  of  large  masses  of  metal 
and  in  the  time  required  to  effect  that  pur- 
pose. The  action  of  a  magnetic  pole  dimin- 
ishes so  rapidly  with  the  increase  of  distance 
that  it  may  suffice  to  remove  the  armature  to  a 
distance  relatively  small  compared  with  its 
own  dimensions,  or  with  those  of  the  magnet, 
in  order  to  reduce  the  action  to  a  negligible 
value.  But  if,  as  in  the  accompanying  illustra- 
tions, Figs.  313  and  314,  the  magnet  N  8  and 
the  armature  a  being  at  a  certain  distance,  we 
bring  between  them  a  piece  of  iron  or  nickel  d, 
then  the  magnetic  force  upon  a  is  immediately 
and  very  considerably  increased.  In  modern 
terms,  the  resistance  of  the  magnetic  circuit 
has  been  reduced  by  the  introduction  of  a 
better  magnetic  conductor,  and  the  number  of 
lines  of  force  passing  through  a  is  proportion- 
ately increased.  The  mass  of  the  piece  d  may, 
moreover,  be  relatively  small,  compared  with 
*  See  The  Electrical  World,  August  27,  1888. 


that  of  iV#anda.  If  d  be  again  withdrawn 
the  magnetic  resistance  is  increased,  and  the 
lines  through  a  are  again  a  minimum. 

Now  it  is  evident  that  we  can  also  obtain  the 
same  effect  by  sufficiently  heating  or  cooling 
the  intermediate  piece  d,  and,  again,  with  a 
broad  field,  we  can  alter  the  distribution  of  the 
lines  at  will  by  heating  or  cooling  one  side  of 
this  piece  or  the  other.  For  this  reason  we 
will  call  the  piece,  rf,  the  thermo-magnetic  dis- 
tributor, or,  briefly,  the  distributor. 

We  will  now  describe  the  manner  in  which 
this  principle  has  been  realized  in  the  practical 
construction  of  both  a  thermo-magrietic  gene- 
rator and  a  motor.  Fig.  31 3  shows  an  elevation 
and  part  section  of  one  of  the  arrangements 
employed.  Fig.  314  is  a  plan  of  the  same  ma- 
chine (in  the  latter  the  ring  a  a  appearing  on  a 
higher  plane  than  it  actually  occupies).  N  8 
is  an  electro-magnet,  a  a  the  armature,  wound 
as  a  Gramme  ring,  and  fixed  to  a  frame  with 
four  arms,  which  can  turn  freely  upon  a  pivot 


FIG.  314. — MENGES'  PYROMAGNETIC  GENERATOR- 
MOTOR. 

midway  between  the  poles.  The  cross  arms  of 
the  frame  are  attached  at  1,2,  3,  4,  Fig.  314. 
Between  the  magnets  and  the  armature  is  placed 
the  distributor  d  d,  where  it  occupies  an  annu- 
lar space  open  above  and  below.  Both  the  mag- 
nets and  the  armature  are  coated  with  mica,  or 
some  other  non-conductor  of  heat  and  electricity 
on  the  sides  facing  the  distributor.  The  distrib- 
utor is  attached  to  and  supported  by  the  cross- 
arms,  so  that  it  turns  with  the  armature. 


THERMO- MAGNETIC  MOTORS. 


277 


Tlie  distributor  is  composed  of  a  ribbon  of 
iron  or  nickel  bent  into  a  continuous  zig-zag. 
This  form  has  the  advantage  of  presenting,  in 
the  cool  part  of  the  distributor,  an  almost 
direct  path  for  the  lines  of  force  between  the 
poles  and  the  armature,  thus  diminishing  the 
magnetic  resistance  as  far  as  possible.  At  the 
same  time  the  Foucault  currents  are  minimized. 
To  the  same  end  it  is  useful  to  slit  the  ribbon, 


ilium. 


FIG.  315. — MERGES'  PYROMAGNETIC  GESTERATOII- 
MOTOB. 

as  in  Fig.  315  ;  this  also  facilitates  the  folding 
into  zig-zags. 

The  distributor  is  heated  at  two  opposite 
points  on  a  diameter  by  the  burners  b  b,  above 
which  are  the  chimneys  e  e.  The  cooling  of 
the  alternate  sections  is  aided  by  the  circula- 
tion of  cold  air,  which  is  effected  by  means  of 
the  draught  in  the  chimneys  a  e.  At  the  points 
of  lowest  temperature  a  jet  of  air  or  water  is 
maintained.  The  cross-arms  are  insulated  with 
mica  or  asbestos  at  the  points  where  they  ex- 
tend from  the  armature  to  the  distributor. 

It  will  now  be  evident  that  while  the  dis- 
tributor is  entirely  cool,  many  of  the  lines  of 
force  pass  from  N  8  without  entering  the  arm- 
ature core ;  but  if  heat  is  applied  at  the  points 
1  and  2  in  the  figure,  so  as  to  increase  the 
magnetic  resistance  at  these  points,  then  a  large 
portion  of  the  lines  will  leave  the  distributor 
and  pass  through  the  armature  core.  Under 
these  conditions,  so  long  as  heat  is  applied  at 
two  points  equidistant  from  ^Vand  S,  we  might, 
if  we  so  pleased,  cause  the  armature  to  be 
rotated  by  an  external  source  of  power,  and  we 
should  then  have  an  E.  M.  F.  generated  in  the 
armature  coils ;  that  is  to  say,  the  machine 
would  work  as  an  ordinary  dynamo,  and  the 
power  expended  in  driving  the  armature  would 
be  proportionate  to  the  output. 

Suppose  next  that  the  points  of  heating,  and 
with  them  the  alternate  points  of  cooling  90 
degrees  apart,  are  shifted  round  about  45  de- 
grees, so  that  the  two  hot  regions  are  no  longer 


symmetrically  situated  with  respect  to  each 
pole  of  the  field.  The  distribution  of  the  mag- 
netization has  therefore  become  unsymmetrical, 
and  the  iron  core  is  no  longer  in  equilibrium  in 
the  magnetic  field.  We  have,  in  fact,  the  con- 
ditions of  Schwedoff's  experiment  upon  a  larger 
scale,  and  if  the  forces  are  sufficient  to  over- 
come the  frictional  resistance  a  rotation  of  the 
ring  ensues  in  the  endeavor  to  restore  equilib- 
rium. The  regions  of  heating  and  cooling 
being  fixed  in  space,  this  rotation  is  continuous 
so  long  as  the  difference  of  temperature  is  main- 
tained. The  ring  in  rotating  carries  with  it  the 
armature  coils,  and,  of  course,  an  E.  M.  F.  is 
generated  in  the  same  way  as  if  the  motive 
power  came  from  an  external  source.  In  this 
respect  the  machine,  therefore,  resembles  a  mo- 
tor-generator, and  the  rotation  is  entirely  auto- 
matic. The  armature  coils  are  connected  with  a 
commutator  in  the  usual  way,  and  the  field  may, 
of  course,  be  excited  either  in  shunt  or  in  se- 
ries. M.  Menges  states  that  the  residual  magnet- 
ization is  sufficient  in  his  machine  to  start  the 
rotation  by  itself.  When  the  machine  is  to  be 


FIG.  316. — MENGES'  PYKOMAGNETIC   GENERATOR- 
MOTOR. 

used  as  a  motor  it  is  evident  that  the  windings 
on  the  armature  core  need  only  be  sufficient  to 
supply  current  to  excite  the  iield,  or  by  the  use 
of  permanent  magnets  they  may  be  dispensed 
with  altogether. 

M.  Menges  has  further  designed  a  large  num- 
ber of  variations  on  the  original  type,  varying 


278 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


the  arrangement  of  the  several  parts,  and  em- 
ploying armatures  and  fields  of  many  different 
types,  such  as  are  already  in  use  for  dynamos. 
In  Fig.  316  a  machine  is  represented  in  which 
the  field  is  external  to  the  armature. 

It  is  evident  that  what  has  been  said  in  refer- 
ence to  the  magnetic  properties  of  the  iron  in 
the  Edison  motor  holds  true  also  in  the  machine 
just  described.  In  the  Journal  of  the  Franklin 
Institute  for  October,  1887,  Mr.  Carl  Hering  dis- 
cusses the  theory  of  pyromagnetic  generators 
of  this  form.  His  remarks  are,  to  a  large  ex- 
tent, applicable  also  to  motors  of  this  class.  A 
study  of  the  principles  involved,  says  Mr. 
Hering,  will  show  that  there  are  practical  limits 
to  the  development  of  such  machines,  some  of 
which  have  been  very  nearly,  if  not  quite, 
reached  in  those  of  the  type  described  above. 
The  chief  one  of  these  is  the  limit  to  the  speed 
of  cutting  of  the  lines  of  force,  and  therefore  a 
limit  to  the  electromotive  force,  or  electrical 
pressure,  which  can  be  generated  with  a  given 
fleld-magnet.  It  is  well  known  that  it  is  the 
electromotive  force  or  electrical  pressure,  and 
not  the  current,  which  is  primarily  generated 
by  any  electrical  generator,  the  current  being 
dependent  on  this  electromotive  force,  the  size 
of  the  wire  and  the  external  resistance.  This 
electromotive  force  is  proportiomil  to  two  fac- 
tors: first,  the  amount  of  magnetism,  or  the 
number  of  lines  of  force,  which  is  practically 
unlimited,  as  the  field-magnets  may  be  made  of 
any  size ;  second,  to  the  speed  with  which  these 
lines  are  cut,  which  in  these  machines  is  de- 
pendent on  the  speed  with  which  the  magnetic 
qualities  of  the  iron  core  may  be  destroyed  and 
restored  by  the  heat.  This  latter  has  a  com- 
paratively low  limit  in  practice,  120  heatings 
per  minute  being,  according  to  Mr.  Edison,  the 
fastest  rate  at  which  these  changes  can  take 
place.  This  means  that  the  useful  lines  of  force 
of  the  field-magnet  can  be  cut  only  240  times  a 
minute,  while  in  the  ordinary  dynamo,  having 
a  speed,  say,  of  1,200  revolutions,  the  lines  are 
cut  2,400  times  a  minute  ;  from  this  alone  it 
would  follow  that  the  amount  of  magnetism  of 
a  pyromagnetic  generator  of  this  kind,  neglect- 
ing all  other  factors,  would  have  to  be  ten  times 
as  great  as  in  a  dynamo  generating  the  same 
potential.  Such  a  generator  is,  therefore,  allied 


to  a  dynamo  having  a  very  low  speed,  and  must, 
therefore,  be  quite  large  as  compared  to  an  ordin- 
ary high-speed  dynamo  for  the  same  output. 
Other  considerations  will  modify  these  propor- 
tions somewhat,  but  the  machines  of  this  kind 
must  necessarily  be  quite  large  and  heavy. 
Fortunately,  howevei',  magnetism  is  cheap,  and 
the  large  size  and  heavy  weight  of  a  machine  is 
not  always  a  very  objectionable  quality;  it  is 
outweighted  many  times  by  the  fact  that  such 
a  machine  is  stated  to  require  no  more  attend- 
ance than  that  required  for  an  ordinary  furnace 
for  heating  houses. 

Another  feature  of  these  machines,  and  one 
which  will  no  doubt  present  many  serious  diffi- 
culties, is  that  the  iron  cores  which  are  to  be 
heated  and  cooled  so  rapidly,  must  necessarily 
be  made  of  very  thin  metal,  and  as  it  has  to  be 
heated  to  redness  to  destroy  the  magnetic 
qualities,  it  is  evident  that  rapid  oxidation  and 
disintegration  of  the  metal  will  take  place, 
which  will  seriously  affect  the  life  of  those 
parts  of  such  a  machine.  This  feature,  may, 
however,  not  be  an  insurmountable  obstacle, 
and  opens  a  sphere  for  inventive  genius  or  for 
discovery. 

In  order  to  complete  the  historical  record  of 
this  class  of  machines,  we  would  mention  that, 
shortly  after  the  publication  by  Mr.  Edison 
of  his  new  form  of  pyromagnetic  generator 
and  motor,  Mr.  Emile  Berliner,  of  Washington, 
D.  C.,  announced  that  he  had  some  time  before 
already  applied  for  a  patent  on  a  therm  o-mag- 
netic  generator  embodying  similar  principles.* 
We  would  also  draw  attention  to  the  investiga- 
tions of  Mr.  E.  G.  Arheson  in  this  field. f 

The  limits  of  this  work  do  not  permit  of  a 
more  detailed  treatment  of  the  thermo-mag- 
netic  properties  of  iron  and  other  magnetic 
metals,  an  important  factor  in  this  class  of 
motors,  but  the  reader  will  find  the  subject 
treated  at  considerable  length  in  the  researches 
of  Rowland — already  referred  to  above — Hop- 
kinson,  Ewing,  Tomlinson,  and  others.  A 
valuable  and  succinct  account  will  also  be  found 
in  the  Encyclopedia  Brittanica,  9th  Ed.,  under 
the  head  of  "Magnetism." 

*  For  the  full  patent  specification  and  drawings,  ,«ee  The 
Electrical  World,  Sept.  10,  1887. 

I  See  Tli,   /•:/,,  ti-iml  World,  Feb.  25,  1888. 


APPENDIX. 


DEVELOPMENT    OK   THE    ELECTRIC    MOTOR    SINCE    1888. 


THE  past  two  years  have  made  an  immense 
change  in  the  status  of  the  electric  motor.  At 
the  time  when  the  last  edition  of  the  present 
volume  was  published  the  art  of  the  electrical 
transmission  of  energy,  and  the  mechanisms 
for  accomplishing  it,  were  in  a  state  wonderful, 
to  be  sure,  when  viewed  from  the  standpoint  of 
a  decade  ago,  but  far  behind  what  they  are  at 
present.  In  particular  the  electrical  street  rail- 
way, perhaps  the  most  interesting  and  impor- 
tant development  of  recent  years,  was  in  its 
infancy.  Inventors  were  struggling  with  the 
practical  problems  involved  in  that  special 


so,  giving  an  account  of  every  inventor  whc 
has  toiled  or  dabbled  in  this  particular  field, 
woidd  occupy  more  space  than  is  appropriate. 
We  shall  simply  give  a  brief  account  of  the 
systems  in  use  to-day,  referring  our  readers 
for  details  of  their  performances  to  the  current 
technical  journals. 

The  first  electric  road  on  a  considerable  scale 
was  that  at  Richmond,  Va.,  the  scene,  a  little 
more  than  two  years  ago,  of  Mr.  F.  J.  Sprague's 
experimental  work.  It  was  an  unqualified 
success  in  spite  of  the  crudeness  of  the  appara- 
tus employed,  and  since  then  the  number  of 


FIG.  317. — EARLY  SPRAGUE  MOTOR  TRUCK. 


task,  but  the  electric  roads,  even  in  an  experi- 
mental stage,  could  be  counted  on  the  ringers 
of  one  hand.  To-day,  electric  traction  is  so 
familiar  that  it  may  seem  almost  superfluous  to 
indulge  in  a  description  of  the  apparatus  that 
is  in  everyday  use;  especially  as  in  two  years 
more  much  of  it  will  have  only  the  same  his- 
torical value  that  the  early  experiments  de 
tailed  in  this  volume  have  to-day.  We  shall, 
therefore,  make  no  attempt  to  give  a  complete 
description  of  the  advances  in  electrical  trac- 
tion, or  of  the  apparatus  employed,  for  to  do 


roads  has  run  up  into  the  hundreds,  the  num- 
ber of  cars  into  the  thousands.  Mr.  Sprague's 
first  practical  form  of  motor  truck  bears  little 
resemblance  to  that  described  in  Chapter  XII. 
The  principles  involved  are  much  the  same, 
the  details,  however,  widely  different.  In  the 
early  model  used  on  the  Richmond  road  two 
1\  horse-power  motors  were  employed ;  one 
end  of  each  motor  frame  was  pivoted  on  the 
car  axle,  the  other  end  supported  flexibly  by  a 
spring.  The  magnetic  circuit  was  of  the  con- 
sequent pole  type,  and  the  armature  was  drum 


280 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


wound,  with  a  commutator  at  each  end,  the 
latter  device  mainly  for  the  purpose  of  enabling 
the  brushes  to  be  very  easily  accessible.  The 
armature  was  wound  in  24  sections,  three  layers 


; 

ff 

I 

•fb 

ni 

inUL 

-a 

ULInr 

-b 

- 

n  D 

+  0 

DD 



-0 

— 

+AJ 

- 

+A, 

-A. 

- 

r 

G 

FIG.  318.— SPRAGUE  SWITCH  Box. 

of  wire  being  in  parallel.  The  armature  core 
was  about  10  inches  in  diameter,  and  perfectly 
smooth. 

Fig.  317  gives  a  view  of  the  early  Sprague 
truck,  equipped  with  two  such  motors.     These, 


turn  current  on  and  off,  but  to  regulate  the 
speed  of  the  motor  by  changing  the  effective 
number  of  amp  re  turns  around  the  field  mag 
nets.  The  motors  were  series  wound,  each  field 
coil  being  a  triple  one.  All  the  coils  in  these 
fields  were  brought  to  the  switch  box,  so  that 
the  individual  coils  could  be  thrown  in  series 
or  in  parallel  and  combined  in  different  ways. 
The  switch  box  had  seven  steps,  eacli  repre- 
senting a  combination  or  a  step  from  one  com- 
bination to  another.  The  actual  number  of 
combinations  was  five,  of  which  only  three 
represented  any  considerable  change  in  mag- 
netizing force,  the  other  two  being  very  slight 
modifications.  Fig.  318  gives  a  view  of  the 
somewhat  complex  cylindrical  switch,  repiv 
sented  spread  out  on  a  surface  so  that  its  de- 
tails can  be  more  easily  seen.  On  the  first  step 
of  the  switch  all  three  coils  were  in  series  ;  on 
the  second  step  the  coil  of  highest  resistance  was 
short-circuited  ;  the  third  step  cut  it  out  ready 
to  be  thrown  in  parallel  with  one  of  the  other 
coils ;  on  the  fourth  step  the  low  resistance  coil 


FIG.  319. — KECENT  SPRAGUE  MOTOR  TRUCK. 


like  all  other  street  railway  motors  since, 
weie  wound  for  relatively  high  voltages,  at 
first  for  400  and  afterwards  for  500  volts.  The 
two  machines  were  placed  in  parallel,  and  con- 
trolled from  a  switch  box  at  either  end  of  the 
car.  These  switch  boxes  served  not  only  to 


was  in  series  with  the  other  two  combined  in 
multiple  arc  ;  the  fifth  step  threw  two  coils  in 
parallel  with  each  other,  short-circuiting  lln- 
third ;  the  sixth  step  cut  out  the  latter  :is  a 
preliminary  to  the  seventh,  where  all  three 
coils  were  placed  in  multiple  arc, 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


281 


Tlie  armature  speed  under  ordinary  con- 
ditions was  about  1,1200  revolutions  per  min- 
ute, geared  down  in  transmission  to  the 
axle  very  nearly  12  times.  This  was  accom- 
plished by  a  double  set  of  gears.  The  armature 
pinion  engaged  the  larger  of  a  pair  of  inter- 
mediate gears,  the  smaller  of  which  drove  the 
car  axle  through  an  interior  gear  wheel,  split 
so  that  it  could  be  readily  placed  in  position. 
These  gears  were  originally  of  cast  iron  or  steel, 
but  later  exhaustive  experiments  were  carried 
on  with  a  view  of  obtaining  a  better  wearing 
material.  The  armature  pinion  has  been  made 
of  nearly  every  substance  ever  used  for  gear 
wheels ;  compressed  rawhide  and  vulcanized 
fiber  being  favorites.  No  material,  however, 
can  stand  the  wear  and  tear  of  exposure  to  dirt 
and  mud  for  any  length  of  time.  After  a  num- 


was  but  slightly  altered.  The  system  of  sup- 
plying the  current  to  the  moving  motors  has 
been  in  every  case  the  overhead  bare  trolley 
wire,  strung  over  the  center  of  the  track  from 
cross  wires  carried  on  poles  arranged  in  pairs 
on  opposite  sides  of  the  street.  Sometimes, 
however,  a  modification  has  been  introduced 
by  carrying  the  trolley  wire  from  brackets  ex- 
tending from  a  single  pole  line.  The  efficiency 
of  the  later  motors,  reckoning  it  as  the  ratio 
between  the  power  supplied  and  that  applied 
at  the  car  axle,  amounts  to  very  nearly  65  per 
cent.  A  very  large  proportion  of  the  loss  oc- 
curred in  the  somewhat  cumbersome  gearing, 
for  the  motors  themselves  have  an  efficiency  of 
nearly  90  per  cent. 

During  the  period  in  which  the  Sprague  sys- 
tem was  developed,  the  Thomson-Houston  elec- 


FIG.  320.— THOMSON-HOUSTON  MOTOR  TRUCK. 


ber  of  roads  had  been  equipped  with  this  form 
of  Sprague  truck,  it  became  very  evident  that 
the  motors  were  not  powerful  enough  to  do  the 
heavy  work  required  of  them,  and  a  second 
truck  carrying  two  15  horse-power  motors  was 
brought  out.  This  later  motor  had  a  single 
U-shaped  magnetic  circuit  with  an  armature 
slightly  larger  and  considerably  more  powerful 
tli-in  before,  and  field  coils  of  lower  resistance. 
The  efficiency  of  the  machine  was  thus  de- 
cidedly improved.  The  method  of  hanging  the 
motors  on  the  truck,  and  the  character  and 
combinations  of  the  regulating  mechanism 
were  practically  the  same  as  before.  Fig.  319 
gives  a  view  of  the  later  Sprague  truck,  equip- 
ped with  its  two  motors.  The  gearing  remained 
virtually  unchanged,  and  the  armature  speed 


trie  railway  appeared,  and  very  soon  made  a 
considerable  place  for  itself.  It  employed  the 
same  system  of  supply,  virtually  the  same 
method  of  suspending  the  motors,  and  nearly 
the  same  gearing.  As  will  be  seen  from  Fig. 
320,  which  shows  the  standard  Thomson-Hous- 
ton truck,  the  motors  have  the  same  general 
appearance  as  the  Sprague  motors,  but  differ 
somewhat  in  construction.  Ordinarily  two  15 
horse-power  motors  are  supplied  to  each  truck, 
and  are  run  in  parallel  at  a  pressure  of  about 
500  volts.  While  the  Sprague  system  had  de- 
pended entirely  on  the  high  resistance  of  the 
three  field  windings  in  series  to  choke  down 
the  initial  rush  of  current  while  the  motor  was 
starting  from  rest,  the  Thomson- Houston  en- 
gineers preferred  to  employ  an  external  rheo- 


282 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


stat  for  this  purpose.  The  motor  fields  are 
wound  with  what  are  practically  double  coils, 
one  or  both  being  employed,  as  occasion  de- 
mands. On  starting,  the  rheostat,  semi-circular 


FIG.  321. — THOMSON-HOUSTON  RHEOSTAT. 

in  form,  and  controlled  by  a  sprocket  wheel, 
generally  operated  by  a  handle  on  the  car  plat- 
form, offers  sufficient  resistance  to  check  the 
initial  current.  Afterwards  more  or  less  of  this 
rheostat  is  cut  out,  and  finally  the  motor  coils 
alone  are  in  series.  The  cur- 
rent is  then  said  to  be  "on 
the  end,"  that  is,  both  the 
motor  coils  are  in  circuit. 
A  further  operation  of  the 
switch  throws  the  motors 
"on  the  loop,"  that  is,  only 
one  of  the  magnet  coils  is 
in  use.  It  will  thus  be  seen 
that  the  two  systems  differ 
principally  in  minor  points 
of  mechanical  construction 
and  in  the  means  employed 
for  regulation.  •  In  the 
method  of  distributing  the 
current  supply  the  two  sys- 
tems vary  somewhat.  The 
Sprague  supply  is  from 
a  line  of  feed  wire  ex- 
tended parallel  to  the  trolley  wire  and 
tapped  into  it  at  short  intervals ;  the  Thom- 
son-Houston distribution  is  effected  by  using 
a  rather  larger  trolley  wire  and  feeding  in 


less  frequently.  The  rheostat  (Pig.  321)  per- 
mits, if  necessary,  a  somewhat  nicer  regulation 
than  is  obtained  by  simply  commutating  the 
field  coils,  but  in  practice  the  rheostat  is  for 
the  most  part  cut  entirely  out  and  the  mo- 
tors run  either  "on  the  loop"  or  "on  the 
end."  The  commercial  efficiencies  of  the 
two  are  not  widely  different ;  the  Sprague 
having  perhaps  a  few  per  cent,  the  advan- 
tage, gained,  however,  at  the  expense  of 
a  more  complicated  system  of  field  wind- 
ing. 

Meanwhile  the  Short  railway  motor  had 
undergone  development.    The  considerable 
difficulties  and  questionable  advantages  of 
the  series  system  of  distribution  has  led  to 
a    practical  abandonment  of  the  original 
device,  and    the  system  is  now  operated 
with  two  15  horse-power  motors  per  car, 
run  in  parallel.     The  arrangement  of  the 
Short  field   magnets    is — as  will  be   seen 
by  a  glance  at  Pig.  322,  which  shows  the 
motor  complete — quite  similar  to  that  of  the 
Brush    arc   dynamo,    and   the   armature   has 
the  same  characteristic  form.     It  is  a  closed 
coil  armature,   however,   with  a  commutator 
having  a  considerable  number  of   segments. 


PIG.  322. — SHOKT  RAILWAY  MOTOR. 

The  motors  are  swung  from  the  truck  by  virtu- 
ally the  same  arrangement  employed  in  the 
systems  just  mentioned,  with  the  difference, 
however,  that  from  the  form  of  the  magnets  it 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


283 


lias  proved  advisable  to  swing  clear  of  the  axle 
on  a  massive  wooden  frame  pivoted  at  one  end 
and  supported  flexibly  at  the  other.  The  gear- 
ing is  of  the  same  character  as  in  the  Spragne 
and  Thomson-Houston  systems,  and  the  arma- 
ture speed  somewhat  lower.  The  construction 
of  the  motor  makes  the  armature  singularly 
easy  to  get  at  for  repairs,  or  to  take  out  en- 
tirely. Fig.  323  gives  a  good  view  of  the  Short 
motor  truck.  No  efficiency  tests  on  the  Short 
motors  have  been  published,  but  their  com- 
mercial efficiency  probably  does  not  differ 
essentially  from  the  machines  just  mentioned. 
The  Short  motors  are  governed  by  a  rheostat, 
without  the  intervention  of  couirnutating  the 


there  are  a  considerable  number  of  minor  im- 
provements in  the  mechanical  details  that  are 
worth  describing  at  some  little  length. 

The  body  or  skeleton  of  the  motor  consists  of 
only  five  parts ;  the  cast  iron  frame,  the  keeper, 
the  two  pole  pieces,  and  the  brass  casting  join- 
ing the  upper  and  lower  pole  pieces  ;  forming  a 
mechanical  framework  of  a  very  strong  and 
simple  character.  The  cast  iron  frame  carries 
the  car  axle,  the  intermediate  axle  and  the 
armature  in  perfect  alignment  and  parallelism, 
thus  enabling  the  gears  to  mesh  with  great 
exactness.  The  pole  pieces,  as  can  be  readily 
seen,  are  hinged  to  the  keeper,  and  both 
are  linnly  held  in  position  by  the  retaining 


FIG.  323.—  SHOKT  MOTOR  TRUCK. 


field  coils.  The  system  of  distribution  em- 
ployed is  practically  the  same  as  in  the  two 
systems  just  mentioned,  and  the  electro-mo- 
tive force  of  supply  is  500  volts. 

In  the  summer  of  1890  the  Westinghouse 
Electric  Company  entered  the  field  of  electric 
traction  with  a  motor  that,  while  electrically 
very  similar  to  the  Spragne  and  Thomson- 
Houston  machines,  possesses  some  unique 
mechanical  features.  The  motor  proper,  as 
will  be  seen  from  Fig.  324,  is  within  a  square 
iron  frame  that  serves  both  to  support  it  and 
to  furnish  bearings  for  the  counter-shafts  for 
gearing.  It  will  be  seen  at  once  that  there  are 
no  radical  changes  from  the  existing  types,  but 


bolts  through  the  brass  casting  that  joins  them 
at  their  extremities.  When,  therefore,  it  be- 
comes necessary  from  any  cause  to  remove  the 
field  coil,  the  retaining  bolts  are  withdrawn 
and  the  entire  pole  piece  swung  back,  when  the 
coil  can  be  at  once  slipped  off  and  replaced. 
In  the  same  way  the  armature  can  be  removed 
by  opening  the  box  and  lifting  it  out  after  the 
pole  piece  is  swung  out  of  the  way.  In  fact, 
one  man  with  the  aid  of  a  differential  pulley 
and  support  which  can  be  attached  to  the 
motor  frame,  will  have  no  difficulty  in  accom- 
plishing these  operations.  When  the  lower 
pole  piece  is  swung  back,  the  armature  can  be 
passed  through  into  the  pit  if  it  is  desirable  to 


284 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


take  it  out  in  that,  direction.  This  hinged  con- 
struction renders  it  very  easy  ta  get  at  any 
portion  of  the  motor  for  repairs. 

The  gears  are  encased  in  cast  iron  boxes,  oil 
tight,  and  partially  filled  with  grease.  They 
are  thus  entirely  free  from  the  access  of  dust 
and  grit,  and  can  be  continually  and  thoroughly 
lubricated.  This  arrangement  of  the  gear 
wheels  is  the  secret  of  the  fact  that  the  motors 


built  up  of  plates,  each  of  which  is  cut  with  a 
key  way,  so  that  the  entire  inner  structure  of 
the  armature  can  be  locked  firmly  upon  the 
shaft.  The  armature  is  wound  with  due  refer- 
ence to  the  fact  that  street  car  motors  have 
occasionally  to  support  heavy  discharges  of 
current,  beyond  their  carrying  capacity.  The 
double  wires  of  the  armature  are  equivalent  in 
conductivity  to  No.  7  wire,  so  that  there  is 


FIG.  324.— WESTINGHOUSE  STREET  RAILWAY  MOTOR. 


make  an  unusually  small  amount  of  noise.  At 
the  same  time  the  life  of  the  gears  is  improved 
by  the  thorough  lubrication,  and  their  wide 
faces,  five  inches,  give  them  additional  dura- 
bility. The  entire  motor  is  protected  beneath 
by  a  sheet  iron  pan  and  on  the  sides  by  water- 
proof sail-cloth. 

As  to  the  details  of  construction,  the  arma- 
ture is  of  the  usual  drum  type;   the  core  is 


little  danger  of  undue  heating  under  the  sever- 
est strain  of  service.  The  wires  from  the  arma- 
ture are  brought  out  straight  to  the  commuta- 
tor  without  crossing  or  overlapping,  and  the 
surface  of  contact  between  the  wire  and  com- 
mutator is  three  or  four  times  larger  than  that 
used  in  the  earlier  street  car  motors,  thus 
avoiding  what  was,  at  one  time,  not  an  uncom- 
mon fault,  the  destruction  of  the  connections 


DEVELOPMEISTT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


285 


at  that  point.  Particular  care  is  taken  in 
binding  the  armature  wires  to  the  core,  so  that 
there  is  no  danger  of  any  play,  even  under 
the  severe  torque  brought  upon  the  windings. 
Between  the  bearings  and  winding  at  the  head 
of  the  armature  is  placed  a  little  brass  ring  so 
arranged  as  to  throw  out  any  oil  which  creeps 
along  the  shaft,  so  that  it  cannot  affect  the 
commutator. 

The  armature  shaft  is  tapered,  having  the 
greatest  diameter  where  the  core  is  keyed  upon 
it,  and  being  tapered  at  the  ends  to  receive  the 
armature  pinion.  This  is  cut  with  a  corre- 
sponding conical  hole,  an  arrangement  that 
enables  it  to  be  very  readily  removed  and  re- 
placed. The  commutator  lias  been  constructed 
with  the  severe  conditions  of  ordinary  service 
in  mind,  and  experience  has  shown  that  it  is 
thoroughly  insulated,  unlikely  to  get  out  of 
line  from  any  cause,  and  quite  free  from  any  in- 
jurious amount  of  heating. 

In  the  insulation  the  greatest  pains  is  taken 
to  render  the  coils  as  nearly  water-proof  and 
lire-proof  as  possible,  and  where  the  wires  are 
bent  around  under  the  coils,  double  insulation 
is  used,  so  as  to  avert  any  probability  of  short- 
circuiting.  The  wires  are  not  brought  out 
direct  from  the  coils  to  the  terminals,  but 
through  special  castings,  averting  breakage  of 
the  wires  from  continual  jarring  at  the  point 
where  they  leave  the  coils. 

As  to  the  running  gear,  comparatively  little 
need  be  said.  The  wheels  are  all  of  five-inch 
face,  and  are  dressed  down  and  tested  in  posi- 
tion before  leaving  the  shops,  so  that  the 
meshing  between  the  teeth  is  as  precise  as  it 
can  well  be  made.  The  armature  pinions  are 
made  of  forged  steel,  and  it  is  believed  that 
when  running  in  oil  they  will  show  a  life  far 
above  the  ordinary.  The  axle  gears  are  made 
of  selected  iron,  with  solid  webs.  Both  pin- 
ions and  axle  gears  are  tested  with  circular 
jigs,  so  that  the  tapered  hole  brings  each  wheel 
to  exactly  the  proper  position  when  the  gear- 
ing is  set  up.  Cimilar  jigs  were  sent  to  the 
principal  truck  builders,  with  the  request  that 
car  axles  be  made  to  conform  with  it,  so  that 
every  portion  of  the  driving  gear  will  fit  accur- 
ately when  it  is  first  placed  in  position. 

The  distribution  is  by  overhead  trolley  wires 


and  poles,  as  usual.  It  is  evident  from  what 
has  been  said  that  the  Sprague,  Thomson- 
Houston,  and  Westinghouse  systems  possess 
very  many  features  in  common.  The  motors 
are  of  about  the  same  size  and  weight,  have, 
roughly  speaking,  similar  forms  of  magnetic 
circuits,  and  the  same  sized  drum  armatures. 
The  design  of  the  first  has  been  from  the  stand- 
point of  the  electrician  ;  that  of  the  last  from 
the  standpoint  of  the  mechanician  ;  while  the 
Thomson  -  Houston  motor  may  be  said  to  be 
midway  between  the  two.  The  Sprague  motor 
has  been  made  even  more  similar  to  the  others 
by  the  recent  introduction  of  a  small  resistance 
coil,  a  rheostat,  external  to  the  motor  and 
thrown  in  at  the  moment  of  starting,  to  be  im- 
mediately cut  out  as  the  switch  is  turned  to 
the  other  steps.  The  Sprague  motor,  then,  is 
governed  by  commutating  the  field  coils  with 
slight  assistance  from  a  small  rheostat.  The 
Thomson  -  Houston  motor  is  governed  by  a 
rheostat  of  many  sections,  with  an  additional 
modification  introduced  by  cutting  out  part  of 
the  field  winding.  The  Westinghouse  employs 
a  rheostat  of  only  four  sections,  but  otherwise 
follows  the  Thomson  -  Houston  practice  of  a 
double  field  winding.  All  the  three,  and  with 
them  the  Short  motor,  employ  two  15  horse- 
power motors  per  car,  geared  down  twice,  the 
gear  ratio  being  in  each  10  or  12  to  one.  It  has 
been  found  by  experiment  that  two  motors 
thus  placed  on  a  car  never  pull  together  in  per- 
fect harmony,  for  one  is  apt  to  take  more  than 
its  share  of  the  load.  The  result  of  this  and 
the  consequent  uneven  wear  on  the  gears  pro- 
duces a  serious  loss  of  efficiency.  The  double 
gear  itself  wastes  at  least  20  per  cent,  of  the 
power  employed,  and  where  two  motors  are 
used  even  more.  The  first  real  improvement 
in  the  matter  of  gearing  efficiency  was  made 
by  the  introduction  of  gears  running  in  oil- 
tight  cases,  and  therefore  free  from  dirt  and 
thoroughly  lubricated. 

In  connection  with  the  unequal  load,  almost 
certain  to  be  found  in  the  case  of  using  two 
motors  to  a  car,  a  particular  point  of  weakness 
was  found  in  the  connections  employed  in  the 
Sprague  system.  At  a  certain  stage  of  the  field 
commutation  an  unstable  state  was  reached, 
and  one  motor  was  almost  sure  to  take  more 


286 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATION'S. 


than  its  share  of  current.  Consequently,  in  the 
latest  motor  equipments,  manufactured  since 
the  Sprague  Company  was  merged  with  the 
Edison  Company,  equalizing  coils  are  em- 
ployed, consisting  of  series  windings  so  ar- 
ranged that  an  extra  rash  of  current  through  a 
single  motor  will  pass  around  the  fields  of  the 
other  motor,  and  tend  to  restore  equilibrium. 

The  experience  of  a  couple  of  years  has  ren- 
dered it  evident  that  an  armature  speed  so 
high  as  to  require  a  double  gear  reduction 
causes  serious  loss  of  efficiency,  as  has  been 


The  Rae  electric  railway  system  presents 
some  radical  differences  from  any  of  the  others 
heretofore  mentioned.  In  the  first  place,  only  a 
single  motor  is  used.  It  is  rigidly  attached  to 
the  truck,  and  the  armature  spindle  is  parallel 
to  the  length  of  the  car.  The  power  is  trans- 
mitted to  both  axles  from  the  same  motor 
through  beveled  gearing.  Fig.  325  gives  an 
excellent  idea  of  the  principal  characteristics 
of  the  system.  As  will  be  seen  at  once,  the 
motor — of  the  consequent  pole  type — is  placed 
crosswise  of  the  car  midway  between  the 


i-°.i -i.p.l^—      r----4--l 14 I--P—  L-4— .  — - --- — -^--i- ^r?-1 .-- 

11 JL^JV  I  i  '  /l_^  i"  i  r    i — *^(f *ff f^f *r?f — i 1 i    n  '-  iv+.       •       ,  i?i  — — r  — 


FIG.  325— RAK  MOTOR  TRUCK. 


mentioned  before,  and  of  late  the  efforts  of  all 
the  railway  companies  have  been  bent  towards 
securing  lower  speed  machines.  In  addition, 
there  has  been  a  growing  tendency  towards  the 
use  of  a  single  motor,  which  may,  perhaps,  be 
best  illustrated  by  the  Fisher- Rae  system,  be- 
fore going  on  to  describe  the  evolution  of  the 
slow  speed  motor,  and  the  consequent  abolition 
of  one  or  both  sets  of  the  gearing  that  had  been 
so  productive  of  waste  of  power  and  frequent 
repairs. 


wheels,  and  fastened  rigidly  to  the  frame-work 
of  the  truck.  The  armature  pinion  drives  an 
intermediate  gear  that  through  bevel  wheels 
turns  the  axles.  The  motor  is  of  30  horse- 
power, with  a  Siemens  armature ;  it  is  thor- 
oughly insulated  at  the  sides  by  oak  bars  satu- 
rated with  asphalt,  and  the  employment  of 
rawhide  or  fibre  armature  pinions  still  further 
frees  the  machine  from  danger  of  a  ground. 
The  whole  truck  is  put  together  as  rigidly  as 
possible,  no  attempt  whatever  being  made  to 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


287 


secure  the  usual  flexibility,  which  in  fact  would 
interfere  with  the  action  of  the  system.  The 
motor  is  series  wound,  strongly  made,  and  of 
creditable  efficiency.  The  regulation  of  speed 
is  through  the  interposition  of  a  rheostat  con- 
sisting of  four  coils  that  are  successively  thrown 
in  parallel  arc  with  each  other,  and  finally 
short-circuited.  The  rheostat  with  its  switch 
is  placed  under  the  car,  as  in  the  Thomson- 
Houston,  Short,  and  Westinghouse  systems, 
and  is  operated  from  the  car  platform  by  a 
simple  handle.  The  use  of  the  single  motor  is 
an  advantage,  as  it  somewhat  reduces  the 
weight  of  driving  gear,  simplifies  the  connec- 
tions, and  is  cheaper.  The  use  of  beveled 
gears  is  of  questionable  value,  although  the 
system  is  in  use  on  a  number  of  roads,  and  is 
reported  to  work  very  well.  The  mechanical 
details  of  the  apparatus  are  thoroughly  worked 
out.  The  beveled  gears  run  in  oil,  and  all  the 
bearings  are  bushed  with  graphite.  These  good 
mechanical  features  probably  go  far  to  off- 
set some  of  the  apparent  disadvantages.  The 
method  of  distribution  and  the  minor  details  of 
the  system  present  no  striking  peculiarities, 
although  the  electro-motive  force  is  intended  to 
rise  as  high  as  550  volts,  rather  more  than  is 
employed  in  general  electric  railway  practice. 
The  use  of  a  single  large  motor,  as  employed 
by  Mr.  Rae,  enables  the  armature  speed  to  be 
somewhat  reduced,  and,  as  a  matter  of  fact,  it 
does  not  rise  above  900  revolutions  per  minute 
at  the  full  speed  of  the  car. 

But,  in  spite  of  the  advantage  of  the  single 
motor,  the  Rae  system,  like  all  the  others  pre- 
viously mentioned,  employs  a  double  set  of 
gearing,  and  consequently  loses  nearly  25  per 
cent,  of  the  power  applied.  To  secure  a  high 
commercial  efficiency  for  any  electric  railway 
system  it  is  necessary  to  diminish  the  amount 
of  gearing  employed  in  transmitting  the  power 
from  the  armature  spindle  to  the  axle,  and 
after  about  two  years'  experience  with  the 
modern  electric  railroad  the  attention  of  a 
number  of  inventors  was  simultaneously  drawn 
towards  the  problem  of  producing  a  low  speed 
motor,  the  armature  spindle  of  which  should 
carry  a  pinion  to  engage  directly  the  gear 
wheel  upon  the  car  axle.  No  practical  ma- 
chine of  this  sort  appeared  until  the  summer  of 


1890,  when  the  Wenstrom  Company  of  Bal- 
timore, Md.,  brought  out  a  very  efficient  and 
well  designed  motor  that  possessed  this  valua- 
ble property  of  slow  speed.  In  addition  several 
ingenious  new  devices  were  embodied  in  the 
car  equipment. 

The  Wenstrom  system  is  in  some  respects  a 
very  radical  departure  from  previous  street 
railway  practice,  and,  as  such,  is  worth  more 
than  a  passing  notice.  It  has  not  yet  been  put 
into  operation  on  a  road  of  its  own,  although 
the  preliminary  experiments  have  met  with 
very  gratifying  success. 

To  begin  at  the  beginning,  it  is  worth  while 
saying  something  of  the  Wenstrom  generator. 
Although  the  machine  is  by  no  means  new,  yet 
there  have  been  recent  and  important  improve- 
ments. The  Wenstrom  machine  has  for  its 
fundamental  point  in  design  a  short  magnetic 
circuit  as  nearly  closed  as  the  mechanical  exi- 
gencies of  the  case  will  allow.  The  type  of 
field  magnet  is  that  which  has  come  to  be 
known  as  the  "iron  clad,"  where  the  magnetic 
circuit  completely  shuts  in  the  armature  and 
field  coils,  so  that,  as  one  looks  at  the  machine 
from  the  outside,  nothing  is  visible  except 
smooth,  easily  curved  surfaces  of  iron.  The 
merits  of  the  type  are  two :  Absence  of  ex- 
ternal magnetism,  and  economical  and  con- 
venient arrangement  of  the  magnetizing  coils. 

Perhaps  the  most  extraordinary  feature  of 
the  Wenstrom  machine  is  the  armature,  which 
does  not  present  the  familiar  appearance  of 
a  core  wound  with  wire,  but  rather  seems  to 
be  a  smooth  cylindrical  mass  of  iron  turned 
and  polished  on  the  exterior  and  barely  out  of 
contact  with  the  pole-pieces.  The  winding  con- 
sists of  wires  passed  through  apertures  cut 
lengthwise  through  the  core  just  under  the  sur- 
face. These  are  actually  stamped  in  the  iron 
discs  of  which  the  core  is  built  up.  We  may 
then  imagine  the  Wenstrom  armature  as  a 
modified  drum  armature  furnished  with  Paci- 
notti  projections,  closed  over  the  top,  however, 
by  a  thin  casing  of  iron.  As  a  matter  of  fact, 
the  apertures  which  receive  the  windings  come 
within  so  short  a  distance  of  the  external  sur- 
face of  the  armature  that  only  a  very  small 
amount  of  magnetism  is  lost  by  leaking  around 
the  armature  on  the  outside  of  the  wires,  while 


288 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


the  complete  freedom  from  external  winding 
allows  this  type  of  armature  to  be  run  with  a 
gap  in  the  magnetic  circuit  enormously  less 
than  can  be  found  in  any  other  construction. 
As  a  natural  consequence  the  magnetism  is 
cheaply  obtained,  and  the  armature  wires  are 
subjected  to  a  very  powerful  induction. 

The  street  car  motor  shown  in  diagram  (Fig. 
326)  has  all  the  characteristic  features  of  the 
generator,  although  the  frame  does  not  retain 
the  cylindrical  form,  but  is  flattened  into  a 
somewhat  more  compact  shape.  It  is,  like  the 
generator,  a  four-pole  machine,  the  magnetic 
circuit  being  cast  of  mitis  metal  in  one  piece, 
with  two  consequent  and  two  salient  poles. 


The  standard  street  car  motor  is  rated  at 
25  horse-power  and  weighs,  complete,  very 
nearly  one  ton.  Owing  to  the  powerful  mag- 
netic field  practicable  with  the  "\Venstrom  con- 
struction, and  to  the  fact  of  the  new  motor  be- 
ing a  four-pole  machine,  its  speed  is  only  400 
revolutions  per  minute.  The  armature  can 
consequently  be  geared  directly  to  the  car  axle 
without  the  intermediate  countershaft  that  has 
been  the  subject  of  frequent  objurgations  from 
every  electric  railway  man  who  has  been  in  the 
business  long  enough  to  have  gearing  give  out. 
A  small  convenience  which  should  be  men- 
tioned here  is  that  the  brush  holder  is  fitted  to 
the  outside  of  the  bracket  that  supports  the 


FIG.  3^6. — WENSTROM  RAILWAY  MOTOR. 


The  frames  that  sustain  the  armature  are  bolted 
to  the  sides  of  the  field  magnets  and  are  readily 
removable,  permitting,  therefore,  the  removal 
of  the  armature  and  consequently  of  the  field 
coils,  which,  when  the  armature  is  taken  out, 
can  be  slipped  off  the  pole-pieces  with  great 
readiness.  The  armature  is  of  the  same  type 
as  that  of  the  generator  and  runs  within  one- 
sixteenth  of  an  inch  of  the  pole-pieces.  The 
commutator  is  provided  with  two  brushes  only, 
90  degrees  apart,  the  armature  being  cross- 
connected  so  that  this  arrangement  is  possible. 
For  convenience  in  taking  off  the  armature  the 
pinion  seat  is  tapered,  so  that  the  armature 
pinion  can  be  very  readily  slipped  off. 


armature  on  the  commutator  end,  so  that  it  can 
be  adjusted  or  taken  off  without  loosening  the 
armature  frame  at  all.  The  absence  of  inter- 
mediate gear  in  the  Wenstrom  motor  is  a  very 
considerable  advantage,  as  it  has  already  been 
mentioned  that  losses  in  gearing  may  rise 
to  a  serious  amount  in  the  motors  now  in  use. 
The  standard  construction  adopted  for  the 
Wenstrom  street  car  system  is  a  single  25 
horse-power  motor  geared  to  one  axle,  the  split 
gear  being  preferably  of  the  wooden  tooth  con- 
struction recently  introduced.  Perhaps,  how- 
ever, the  most  ingenioiis  modification  of  pres- 
ent street  car  practice  is  to  be  found  in  the 
hydraulic  gear  which  forms  the  connection 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


between  the  split  gear  and  the  driven  axle. 
This  has  been  but  recently  worked  out,  and  its 
purpose  is  to  furnish  a  variable  clutch  between 
the  driving  and  the  driven  axle,  so  that  in 
starting  the  motor  it  may  be  allowed  to  run 


FIG.  327. — SECTION  OF  HYDRAULIC  CLUTCH. 

free  and  its  power  applied  gradually  to  start 
the  car,  and  in  addition  to  provide  a  sort  of 
mechanical  safety-valve,  so  that  when  there  is 
a  severe  overload  the  hydraulic  clutch  will  slip 
and  allow  the  armature  to  rotate  fast  enough 
to  save  it  from  the  excess  of  current,  instead  of 
subjecting  it  to  the  dangerous  overloading 
which  would  otherwise  follow. 

Fig.  327  shows  a  section  of  this  hydraulic 
gear.  It  consists  of  a  cylindrical  cavity  placed 
eccentrically  to  the  driving  shaft  and  turned 
up  true  and  smooth  within.  It  is  fitted  with  a 
tight  cover  firmly  bolted  on.  Through  a  disc 
fast  to  the  axle  slides  a  brass  key,  forming  a 
partition  across  the  eccentric  box  free  to  slide 
as  the  shaft  turns,  and  forcing  the  oil  with 
which  the  eccentric  box  is  filled  through  a  port 
in  the  rim  connecting  one  side  of  the  cavity 
with  the  other.  The  arrangement  thus  forms 
a  rotary  circulating  pump  of  which  this  brass 
slide  is  the  piston  and  the  eccentric  box  the 
pump  cylinder.  So  long  as  the  port  between 
the  two  sides  of  the  piston  is  open  the  eccentric 
box  can  revolve  freely,  forcing  the  oil  around 
through  the  port  as  it  turns.  If,  however,  the 
port  is  closed,  the  oil  can  no  longer  flow  and 


forms  an  incompressible  mass  through  which 
the  power  is  transmitted  to  the  axle.  The 
arrangement  is  equivalent,  as  before  remarked, 
to  a  rotary  pump,  the  piston  of  which  is  free 
to  move  within  the  cylinder  so  long  as  the 
valves  are  open.  When  they  are  closed,  piston 
and  cylinder  must  move  together,  if  at  all. 
The  result  of  this  arrangement  is  that,  the  port 
being  open,  the  split  gear  to  which  the  appara- 
tus is  applied  rolls  freely  around  on  the  axle 
without  communicating  any  motion  to  it.  If, 
however,  the  valve  be  closed,  the  gear  and  axle 
act  as  a  rigid  body  and  the  motor  can  exert  its 
full  force.  Suppose  the  car  to  be  at  rest  and 
the  valve  and  hydraulic  gear  open,  the  motor 
on  starting  will  revolve  freely.  Now  gradually 
close  the  valve ;  as  the  passage  for  the  oil  is 
more  and  more  contracted  a  greater  and  greater 
pressure  will  be  exerted  tending  to  turn  the 
axle,  and,  although  during  this  period  there 
will  be  some  slip,  finally,  as  the  valve  closes, 
the  pressure  is  sufficient  to  start  the  car,  and 
when  the  by-passage  is  completely  closed,  gear 
and  axle  act  as  a  rigid  body,  and  there  is  no 
appreciable  amount  of  slip.  It  will  be  seen 
that  this  hydraulic  gear  enables  a  flexible  con- 
nection to  be  made  between  the  axle  and  the 
gear,  so  that  the  latter  will  run  freely  or  with 


FIG.  328. — HYDRAULIC  CLUTCH  IN  POSITION. 

varying  amounts  of  resistance  and  slip  up  to 
the  point  where,  when  the  valve  is  completely 
closed,  the  two  are  to  all  intents  and  purposes 
rigidly  connected.  It  is  worth  while  thus  to 
go  into  details  concerning  this  unique  contriv- 


290 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


ance,  for  the  reason  that,  while  it  is  simple,  its 
exact  action  might  not  be  at  first  sigh  obvious. 
Fig.  328  shows  the  hydraulic  gear  as  attached 
to  the  corresponding  wheel.  It  is  not  a  bulky 
contrivance,  and  is  under  perfect  control  from 
the  platform  of  the  car,  from  which  point  the 
valve  car  be  regulated.  It  allows  the  armature 
to  run,  if  desired,  at  a  constant  speed,  whether 
the  car  is  going  at  its  full  rate  or  standing  still. 
Perhaps,  however,  its  greatest  convenience  is 


fitted  to  any  of  the  eight  -wheeled  forms  of 
truck,  even  above  the  car  floor,  if  desirable. 

The  next  slow  speed  motor  to  appear  was  the 
Baxter,  still  another  development  of  the  multi- 
polar  type  of  machine. 

The  armature  in  the  Baxter  street  railway 
motor  is  18  inches  in  diameter,  and  at  each  end 
of  the  armature  shaft  are  4|-inch  pinions  which 
gear  in  the  18-inch  wheels  on  the  car  axle ;  the 
speed  of  the  armature,  therefore,  is  four  times 


FIG.  329.— BAXTER  MOTOR  TRUCK. 


in  the  matter  of  applying  the  power  gradually 
at  the  start,  so  as  to  avoid  straining  the  arma 
ture  or  producing  an  unpleasant  jar.  In  apply- 
ing the  Wenstrom  motor  and  the  hydraulic 
driving  gear  to  a  car  equipment,  any  of  the 
usual  arrangements  can  be  employed.  One 
motor  can  be  geared  to  one  or  both  axles ;  two 
motors  can,  in  the  rare  cases  when  it  may  be 
necessary,  be  employed,  or  the  motors  can  be 


as  great  as  that  of  the  wheel,  so  that,  when  the 
car  is  running  at  about  eight  miles  per  hour, 
the  armature  will  turn  at  something  like  335 
revolutions  per  minute.  With  the  cars  ordi- 
narily in  use  the  armature  speed  would  be 
something  like  1,000  per  minute  for  the  same 
rate.  The  motor  of  course  is  multipolar,  hav- 
ing eight  poles  formed  by  four  separate  mag- 
nets, each  having  its  own  magnetizing  coil, 


DEVELOPMENT  OP  THE  ELECTRIC  MOTOR  SINCE  1888. 


291 


placed  so  that  the  poles  alternate  around  the 
armature.  The  core  of  the  armature  and  the 
hub  of  the  motor  are  insulated  with  particular 
care  to  avoid  the  short  circuits  which  some- 
times occur  through  grounding  on  the  frame  of 
the  motor.  The  motor  is  series  wound  and  has 
the  various  segments  of  the  armature  coils  con- 
nected in  series  by  a  special  method  devised  by 
Mr.  Baxter.  The  conductors  lie  in  grooves  on 
the  exterior  of  the  armature,  so  that  the  Paci- 
notti  construction  is  really  the  one  followed. 
The  brush  holders  are  composed  of  two  sliding 
castings,  so  arranged  that  the  upper  can  be 
pulled  out  of  place  in  an  instant  with  the 


noise  that  is  produced  is  much  muffled  and  the 
car  runs  very  quietly  and  easily.  All  bearings 
are  diist-tight,  and  are  self-oiling.  The  motors 
are  suspended  something  after  the  usual 
method,  but  the  suspension  rod  is  some  six  or 
seven  inches  long  and  prevents  the  motor  from 
slipping  Tap  and  down,  although  it  does  not  re- 
strain lateral  motion ;  therefore,  if  the  car  or 
truck  should  sway  even  an  inch  or  two,  no 
strain  will  be  brought  upon  the  motors  or  gear- 
ing. In  addition  to  this  the  end  of  the  motor 
next  to  the  suspension  moves  with  the  car,  and 
there  is,  therefore,  little  vibration  at  this  point 
where  the  circuit  wires  are  connected  from 


FIG.  330. — THOMSON-HOUSTON  SLOW  SPEED  MOTOK. 


fingers,  and  the  brush  removed  and  replaced 
again  just  as  quickly.  The  solidity  of  con- 
struction in  the  brush  holders  prevents  vibra- 
tions of  the  brushes,  and  aids  them  to  run 
without  any  visible  sparking.  Both  brushes 
are  on  the  upper  side  of  the  commutator  in  full 
view.  The  illustration  on  the  preceding  page 
(Fig.  329)  gives  a  good  idea  of  the  construction 
of  the  motor  and  its  method  of  application  to 
the  truck. 

The  gears  are  inclosed  in  an  oil-tight  cham- 
ber, so  that  they  are  perfectly  lubricated  and 
protected  from  dust  and  grit  which  would  tend 
to  wear  them  loose.  In  this  way  the  little 


the  motor  to  the  switches,  so  that  there  is 
very  little  liability  of  bad  connections.  In 
addition  a  dust-tight  casing  is  presented  to 
cover  over  the  entire  machine. 

The  governing  is  by  rheostat,  and  the  car  is 
operated  by  a  single  crank  shaft.  Turning  it 
in  one  direction  the  car  moves  forward,  in  the 
other  direction  reverses,  and  the  speed  of  the 
car  is  controlled  by  the  distance  through  which 
the  crank  is  turned.  In  addition  to  securing 
slow  speed  by  the  multipolar  construction  a 
high  weight  efficiency  is  also  obtained,  so  that 
the  two  motors,  each  of  20  nominal  horse- 
power, weigh  together  but  3,000  pounds.  This 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS 


is  considerably  lighter  than  the  usual  street  car 
motors,  which  weigh  from  2,000  to  2,500  pounds 
apiece.  The  rheostat  and  regulating  apparatus 
is  placed  between  the  motors  under  the  car 
floor,  and  therefore  can  be  easily  reached  by 
opening  the  trap  doors.  The  lightning  arrest- 
ers are  placed  in  the  same  situation  and  are  in 
series  with  the  rheostat,  which  serves  as  a 
choking  coil  to  afford  additional  protection. 

As  in  the  case  of  the  Wenstrom,  the  Baxter 
motor  has  at  the  date  of  writing  no  extensive 
commercial  use,  but  it  is  of  interest  as  a  meri- 
torious endeavor  to  improve  street  railway 
practice,  and  as  a  f orerunner  of  the  slow  run- 
ning motor  type.  For  once  the  larger  electric 


round  the  armature  core.  The  magnetic  cir- 
cuit is  completed  on  the  front  end  of  the  motor 
through  the  face  plate  and  at  the  back  through 
the  frame,  on  which  are  cast  the  axle  boxes 
and  arms  that  serve  as  a  support  for  the 
armature  shaft  bearings.  The  armature  is  of 
the  Gramme  ring  type,  and  the  bobbins  are 
wound  close  together  around  the  entire  rim. 
One  great  advantage  of  this  construction  is  the 
fact  that  any  coil  can  be  easily  rewound  with- 
out disturbing  its  fellows,  while  with  the  drum 
armature  in  the  type  of  motor  formerly  used 
by  the  company  the  winding  all  had  to  be  re- 
moved down  to  the  injured  coil. 

The  brushes  are  placed  exactly  opposite  and 


Fiu.  331. — DETAILS  OP  THOMSON-HOUSTON  SLOW  SPEED  MOTOR. 


companies  were  behindhand,  but  during  the 
first  months  of  1801  the  Thomson-Houston  and 
Westinghoiise  companies  brought  out  motors 
for  street  railway  service  having  the  same  valu- 
able property  of  slow  speed.  The  first  of  these 
is  notable  as  being  a  two-pole  machine.  It  has 
been  the  subject  of  much  experiment  on  the 
part  of  the  Thomson-Houston  company  and 
has  been  named,  from  its  construction,  the 
"single  reduction  gear"  motor,  but  is  ordi- 
narily called  the  "S.  R.  G."  As  will  be  seen 
by  Fig.  330,  the  motor  is  very  nearly  iron  clad, 
having  two  pole  pieces  of  ample  surface  and 
carrying  two  field  coils,  which  partially  sur- 


in  a  horizontal  fixed  position.  There  seems  to 
be  no  sparking  under  the  ordinary  running 
conditions,  and  the  brushes  are  easy  of  access. 

The  field  spools  are  protected  on  all  sides  by 
the  fields  and  frame.  The  gears  are  entirely 
inclosed  in  a  dust  and  oil-tight  case,  which  is 
provided  with  a  hand-hole  closed  by  a  spring 
cover,  permitting  ready  examination  of  gears 
and  the  introduction  of  lubricants. 

A  sheet-iron  pan  extending  above  the  center 
of  the  armature  shaft  entirely  incloses  the  bot- 
tom and  sides  of  the  motor  and  protects  the 
armature  and  commutator  from  dust,  snow  and 
water.  The  advantage  of  this  casing  was 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


293 


strikingly  demonstrated  during  several  snow 
storms,  the  "S.  R.  G."  coming  through  un- 
harmed, while  some  of  the  fields  on  the  old 
style  of  motor  came  to  grief  from  the  effects  of 
excessive  moisture.  The  pan  has  a  sliding 
bottom,  and  is  attached  to  the  motor  in  such  a 
manner  as  to  permit  of  being  readily  removed 
for  access  to  the  various  parts. 

The  motor  when  mounted  on  a  truck  with 
thirty-inch  wheels  is  designed  to  clear  the  tops 
of  the  rails  four  inches.  The  spur  gear  on  the 
armature  shaft  is  of  steel,  four  and  one-half 
inches  face,  and  has  fourteen  teeth.  The  split 
gear  on  the  car  axle  is  of  cast  iron,  with  the 


displacement  of  coils,  breaking  of  commutator 
connections,  all  insure  a  minimum  amount  of 
expenditure  for  repairs. 

Fig.  331  shows  the  detailed  construction  of 
the  working  parts.  A  glance  shows  the  great 
compactness  that  has  been  attained.  The  field 
castings  fit  snugly  around  the  armature,  and 
the  flat  magnetizing  coils  slipped  over  the  poles 
embrace  the  ends  of  the  armature.  This  is 
perhaps  the  only  objectionable  feature  of  the 
machine,  for  it  necessitates  bunching  the  wires 
that  lead  from  the  armature  tc  the  commutator 
in  a  way  that  demands  the  greatest  care  in  in- 
sulation. The  use  of  mitis  iron  for  the  fields 


FIG.  332. — WESTINUHOUSE  SLOW  SPEED  MOTOR. 


same  width  of  face,  and  has  67  teeth.  The 
speed  of  the  armature  shaft  relative  to  that  of 
the  car  axle  is  nearly  as  4.8  to  1  ;  when  the  car 
is  running  ten  miles  per  hour  the  armature 
makes  538  revolutions  per  minute,  or  the  speed 
of  the  armature  is  53.8  turns  per  minute  when 
the  car  speed  is  one  mile  per  hour.  The  gears 
are  surrounded  by  an  iron  box,  so  that  they 
may  be  run  in  oil. 

The  facility  with  which  the  armature  can  be 
removed  simply  by  lifting  the  upper  field,  the 
ease  with  which  an  armature  bobbin  can  be  re- 
wound, small  liability  to  damage  from  centri 
fugal  action,  such  as  bursting  of  binding  wires, 


is  a  very  important  element  in  making  possible 
the  excellent  efficiency  that  the  motor  has 
shown  under  test.  It  was  a  somewhat  daring 
experiment  to  design  a  two-pole  motor  for  so 
low  a  speed,  but  thanks  to  a  good  magnetic 
circuit  and  a  powerful  armature,  the  result 
has  been  satisfactory.  The  regulation  of  the 
"  S.  R.  G."  motor  is  through  a  rheostat  like 
that  of  the  old  standard  type  of  motor,  so 
that  the  general  car  equipment  presents  no 
especially  novel  features.  In  fact,  the  number 
of  useful  innovations  that  can  now  be  made  in 
the  governing  of  a  series  wound  motor  is  com- 
paratively limited. 


294 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


In  evolving  a  slow  speed  machine  the  "VWst- 
inghouse  Company  adopted  the  four-pole  con- 
struction and  very  ingeniously  designed  it  to 
follow  the  general  mechanical  principles  that 
had  proved  advantageous  in  the  earlier  standard 
motor  of  the  same  make.  After  considerable 
experimenting  the  multipolar  machine  was  put 
upon  the  market  in  the  shape  shown  in  Fig. 
332. 

It  will  be  seen  that  its  general  form  is  cylin- 
drical, giving  both  the  shortest  possible  mag- 
netic circuit  and  very  great  strength  with 


makes  it  possible  to  utilize  four  poles  with 
great  advantage,  and  they  are,  as  will  be  seen 
at  a  glance,  rather  narrow,  and  consequently 
are  capable  of  being  magnetized  by  compar- 
atively short  and  small  windings.  One  of 
these  coils,  together  with  a  brush-holder,  is 
shown  in  Fig.  334.  The  brush-holder  is  a 
solid-looking  casting  bolted  on  to  the  lower 
side  of  the  main  frame  of  the  motor,  and  lift- 
ing its  brushes  quite  up  to  the  top  of  the  com- 
mutator, where  they  rest  90  degrees  apart. 
The  field  coils  are  of  coarse  wire,  and,  by  rea- 


FIG.  333. — FIELD  MAGNETS  OF  WESTINGHOUSE  SLOW  SPEED  MOTOK. 


minimum  amount  of  material.  Besides  this,  all 
the  sharp  corners  that  tend  to  leak  magnetism 
are  eliminated,  and  the  machine  is  rendered 
thereby  slightly  more  efficient.  The  details  of 
the  magnetic  circuit  are  best  shown  by  examin- 
ing Fig.  333,  which  shows  the  casting  freed 
tiom  armature  and  coils  and  opened  up  to  ex- 
hibit its  arrangement.  The  motor  has  the  same 
square  form  of  frame  that  is  aheady  familiar 
in  the  older  Westinghouse  motor.  But  the 
change  in  the  shape  of  the  magnetic  circuit 


son  of  their  small  length  and  low  resistance, 
give  the  necessary  magnetization  without  a 
serious  loss  of  energy.  The  castings  are  of  a 
specially  soft  grade  of  iron  that  has  proved  to 
Iiave  excellent  magnetic  properties. 

Fig.  332  gives  an  excellent  idea  of  the  gen 
era!  arrangement  of  the  motor,  showing  the 
gear  casing— exhibited  by  itself  in  Fig:  335— 
the  arrangement  of  the  fields  and  the  disposi 
tion  ot  the  frame,  supported  as  usual,  on  the 
axle  at  one  end  and  flexibly  at  the  other.     The 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


295 


gearing,  inclosed  as  it  is  in  an  oil-tight  case,  is 
always  thoroughly  lubricated  and  free  from 
dirt.  All  the  bearings  are  bushed  with  metal, 
and  the  armature  shaft  is  slightly  tapered  to 
facilitate  the  removal  of  the  pinion.  The  gear 
ratio  is  3.8  to  1.  The  iron  clad  form  of  the 
motor  enables  it  to  be  completely  shut  in  by 
applying  side  plates,  so  that  in  actual  practice 
it  is  inclosed  so  tightly  as  to  be  quite  free  from 
the  numerous  difficulties  so  often  experienced 
from  dirt  and  moisture  finding  their  way  into 
the  working  parts  of  a  machine.  As  the  lower 
surface  of  the  motor  presents  only  a  solid  cast- 


BKUSH   HOLDER  OF  WESTINGHOUSK  MOTOK. 

ing,  it  cannot  be  injured  by  casual  blows  from 
projecting  rubble,  a  source  of  difficulty  with 
which  electric  street  railway  men  are  only  too 
familiar.  The  cut  also  gives  a  perspective  view 
of  the  motor,  showing  its  arrangement  in  the 
frame  and  connection  to  the  gears.  The  arma- 
ture is  of  the  drum  type,  and  the  core  is  built 
up  of  grooved  iron  plates,  so  that  the  windings 
are  inside  slots  upon  its  surface,  thus  com- 
pletely imbedded  in  insulating  material.  The 
surface  of  the  finished  armature  is  therefore 
entirely  smooth  and  the  clearance  space  very 
small.  Even  should  the  bearings  become  worn 
so  that  the  armature  would  brush  against  the 
pole  pieces,  no  serious  damage  would  be  done 
because  no  wire  is  exposed. 

The  electrical  efficiency  of  the  motor  is  said 
to  rise  to  95  per  cent.,  and  the  commercial  effi- 
ciency to  75  or  76  per  cent.  This  is  an  excellent 
showing,  and  displays  the  slow-speed  motor 
with  a  single  gear  reduction  in  a  very  favorable 
light.  It  is  about  the  figure  that  would  be  ex- 
pected from  a  machine  of  this  construction. 
Inasmuch  as  the  efficiency  of  the  two-pole 
motors  of  various  forms  with  the  complicated 
gear  is  generally  held  to  be  a  little  over  60  per 


cent.,  the  abolition  of  the  intermediate  gear 
ought  certainly  to  be  good  for  more  than  10  per 
cent,  increase  in  efficiency.  The  normal  speed 
of  the  armature  at  a  car  speed  of  aboiit  10  miles 
per  hour  is  380  revolutions  per  minute.  Thus 
it  will  be  seen  that  the  machine  in  question  is 
really  a  very  slow  speed  motor,  the  restilt  of 
good  magnetic  circuits  and  the  four-pole  con- 
struction. The  commutator  is  designed  with 
special  reference  to  obviating  the  heating  that 
is  sometimes  so  disastrous  in  street  car  motors. 
Each  segment  has  a  bearing  along  its  entire 
lower  edge,  so  that  even  if  there  should  be  any 


FIG.  334. 


MAGNETIZING  COIL  OF  WESTINGHOUSE  MOTOR. 

slipping  the  symmetry  of  the  commutator 
would  not  be  destroyed.  The  winding  of  the 
armature  enables  the  two  brushes,  as  before 
mentioned,  to  be  placed  90  degrees  apart,  and 
both  upon  the  top  of  the  commutator,  where 
they  can  be  readily  inspected  or  replaced  if 
necessary. 
Not  content  with  the  reduction  in  speed 


FIG.  335. — GEAR  CASING  OF  WESTINGHOUSE  SLOW 
SPEED  MOTOR. 

gained  in  this  promising  motor,  the  Westing- 
house  Company  set  about  the  task  of  devising 
a  motor  the  armature  of  which  should  be 


296 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


directly  upon  the  car  axle,  thus  doing  away 
with  all  gearing  whatsoever.  The  abolition  of 
the  remaining  gear  would  mean  a  still  further 
increase  of  efficiency,  and  besides,  would  lessen 
the  moving  parts  that  require  repair.  In  less 
than  sixty  days  after  the  single  reduction  gear 
Westinghouse  motor  appeared  the  gearless 
motor  was  in  experimental  operation. 

The  general  appearance  of  the  Westinghouse 
gearless  motor  is  roughly  shown  in  Fig.  336. 
It  is  a  four-pole  machine,  completely  iron-clad, 
and  with  the  same  hinged  arrangement  of 
fields  that  has  proved  so  convenient  in  the 
other  types  of  Westinghouse  motor.  The  ar- 
mature is  built  directly  on  the  car  axle  with- 
out any  attempt  at  flexible  connection  ;  it  is  of 


ance  between  the  bottom  of  the  motor  and  the 
tread  of  the  30-inch  wheel.  The  motor  has  not, 
at  the  time  of  writing,  been  used  in  anything 
but  an  experimental  way,  and  the  details  of  its 
winding  have  been  carefully  kept  secret.  A 
high  efficiency  is  claimed  for  it,  however,  as 
great  as  90  per  cent.,  and  it  is  said  that  after  a 
two  hours'  run  at  a  load  of  over  20  horse-power 
the  rise  in  the  temperature  of  the  armature  and 
field  coils  was  only  30  degrees  centigrade  above 
the  surrounding  air,  showing  at  least  a  tolera- 
bly efficient  electrical  design. 

Almost  simultaneously  with  the  appearance 
of  the  Westinghouse  gearless  motor  came  the 
Short  machine  of  the  same  type.  In  this  mo- 
tor the  same  style  of  armature  is  employed  as 


FIG.  336.— WESTINGHOUSE  GEARLESS  RAILWAY  MOTOR. 


the  drum  type,  16  inches  in  diameter,  and  in- 
stead of  having  a  smooth  surface  is  grooved  to 
receive  the  wires,  thus  holding  them  rigidly  in 
place  and,  of  course,  lessening  the  magnetic 
resistance  of  the  air  space.  The  brush  holder 
is  rigidly  fastened  to  the  magnet  frame,  and  is 
easily  accessible  through  the  openings  shown 
on  the  top  of  the  casting,  which  are  closed 
when  the  car  is  running  by  water-tight  lids. 
The  weight  of  the  magnet  frame  is  counterbal- 
anced and  cushioned  on  heavy  spiral  springs 
resting  on  the  cross-bars  of  the  truck ;  these 
prevent  the  field  from  rotating,  and  give  the 
motor  the  necessary  flexibility  needed  for  easy 
starting.  The  total  depth  of  the  field  magnets 
over  all  is  but  20  inches,  giving  5  inches  clear- 


in  the  ordinary  Short  motor — that  is,  a  flat 
Gramme  ring  of  many  sections,  with  a  mag- 
netic circuit  arranged  like  that  of  the  Brush 
dynamo.  The  motor  and  its  connections  are 
admirably  shown  in  Fig.  337.  The  arma- 
ture itself  is  not  mounted,  as  in  the  Westing- 
house  motor,  directly  upon  the  axle  but  on  a 
hollow  shaft  concentric  with  it,  with  plenty  of 
inside  clearance.  The  armature  proper  consists 
of  a  laminated  iron  core  of  the  usual  Short 
type  wound  in  a  large  number  of  independent 
segments.  The  style  of  construction  obviously 
allows  excellent  ventilation  and  very  free  re- 
winding. The  commutator  is  mounted  on  the 
same  hollow  shaft  as  the  armature  and  close 
to  it.  The  motor  is  really  a  four-pole  ma- 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


297 


chine.  The  clearance  allowed  is  very  small 
and  the  magnetic  field  most  intense.  The  field 
coils  are  bolted  to  a  circular  frame  at  each  side 
of  the  motor,  in  the  center  of  which  are  the 
bearings  that  carry  the  hollow  armature  shaft. 
The  spring  connections  for  easy  starting  are 
shown  in  the  cut.  A  double  arm  running  out 
from  the  frame-work  to  the  cross-girders  of 
the  truck  makes  provision  for  supporting  the 
entire  motor.  The  insulation  between  these 
brackets  and  the  girders  is  by  means  of  heavy 
rubber  bushings  through  .which  the  bolts  pass. 
By  removing  the  bolts  attaching  the  fields  to 
the  supporting  frame- work  the  coils  may  be 
readily  taken  out  for  repairs,  or  for  access  to 
the  armature. 

Fig.   338  gives  a  plan  of  the  truck  equip- 


is  difficult  to  design  for  small  electrical  losses, 
bvit  there  is  every  reason  to  think  that  the 
working  efficiency,  all  things  considered,  is 
decidedly  higher  than  most  of  the  machines  at 
present  in  use,  to  say  nothing  of  the  gain  in 
wear  and  tear  from  the  absence  of  gearing. 
One  of  the  very  convenient  features  of  the 
Short  motor  is  the  ease  with  which  it  can  be  re- 
paired, for  by  loosening  the  four  bolts  support- 
ing the  motor  on  the  truck  and  taking  off  the 
iron  strips  below  the  wheel-box,  one  end  of  the 
car  may  be  jacked  Tip  and  the  axle-wheel  and 
motor  run  out  from  under  the  car  where  they 
may  be  easily  reached.  Armature  repairs 
may  be  made  by  removing  two  field  coils ; 
the  aimature  coil  can  then  be  rewound  as  it 
stands.  The  field  coils  can  be  as  easily  re- 


Fio.  337. — THE  SHOKT  GEARLESS  MOTOK. 


ment,  showing  a  single  motor.  From  the 
center  of  the  axle  to  the  bottom  of  the 
casing  is  12f  inches ;  a  36-inch  wheel  is  gen- 
erally enrployed,  giving  a  clearance  of  5J 
inches  over  the  track.  At  a  speed  of  ten  miles 
per  hour  the  armature  drives  a  36-inch  car- 
wheel  ninety-four  revolutions  per  minute  ;  the 
equivalent  speed  of  a  single  reduction  motor 
would  be  about  four  hundred,  showing  clearly 
enough  the  advantage  of  the  gearless  form. 
The  efficiency  of  the  motor  is  not  stated,  but  it 
is  evident  enough  from  what  has  already  been 
said  that  the  gain  by  the  abolition  of  gearing 
is  sufficient  to  compensate  for  no  small  loss  of 
electrical  efficiency.  So  slow  running  a  motor 


paired,  while  the  commutator  may  be  reached 
and  sandpapered  while  the  machine  is  running, 
as  in  the  ordinary  forms  of  geared  motor.  This 
Short  motor  is  of  special  interest  as  being  by  a 
few  days'  priority  the  first  of  the  direct  con- 
nected motors  to  appear.  It  is  certainly  a  very 
ingenious  and  interesting  machine,  and  may  be 
expected  to  give  a  good  account  of  itself  in 
actual  service,  although  up  to  the  present  it 
has  been  used  only  in  an  experimental  way, 
and  almost  nothing  can  be  told  of  what  will 
be  its  performance  in  commercial  service. 

Several  other  gearless  motors  are  known  to 
be  under  way,  some  of  them  possessing  very 
remarkable  characteristics.  One  of  these  is 


298 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


worth  especial  attention,  although  it  does  not 
properly  belong  in  the  same  category  as  the 
two  just  mentioned.  This  is  the  Eickemeyer 
gearless  motor,  really  earlier  than  either  the 
Short  or  Westinghouse  machines.  In  its  first 
form,  however,  an  attempt  was  made  to  dodge 
the  difficulties  inherent  in  low  speed  by  using 
a  very  small  driving  wheel,  hence  allowing  a 
higher  armature  speed  for  a  given  number  of 
miles  per  hour.  In  machines  now  under  con- 
struction the  driving  wheels  are  of  about  the 
ordinary  size.  The  peculiarity  of  the  Eicke- 
meyer construction  is  the  use  of  a  motor  not 
connected  to  the  axle,  but  operating  through 


singularly  compact.  It  is  mentioned  some- 
what by  itself  as  a  machine  of  radically  differ- 
ent construction  from  the  other  gearless  motors 
described,  and  as  having  in  its  early  form 
possessed  the  extraordinary  characteristic  of 
exceedingly  small  drivers.  In  its  present  type, 
however,  many  improvements  have  been  intro- 
duced and  the  machine  ranks  as  one  of  the 
promising  solutions  of  the  slow  speed  problem 
that  confronts  the  designer. 

None  of  the  gearless  motors  have  been  as  yet 
put  to  any  extensive  trial,  hence  any  account 
of  them  must  necessarily  be  imperfect  and  im- 
satisfactory.  In  the  course  of  the  coming  year 


Fio.  338. — PLAN  OF  SHORT  GEAIU/ESS  MOTOR  IN  POSITION  ox  THE  TRUCK. 


the  medium  of  a  connecting  rod.  A  heavy  disc 
on  the  armature  spindle  is  attached  to  the  car 
wheel  much  as  the  drivers  of  a  locomotive  are 
connected.  The  possible  advantage  of  this  form 
of  construction  is  freedom  from  injury  to  the 
armature  by  jarring  of  the  axle.  As  neither 
this  nor  the  previous  form  of  machine  have 
been  in  anything  but  experimental  use,  how 
much  of  real  value  the  Eickemeyer  construction 
has  cannot  yet  be  told.  The  machine  is  a  thor- 
oughly well  designed  and  efficient  one,  like 
all  that  have  thus  far  been  elaborated  by 
Mr.  Eickemeyer.  The  motor  is  iron-clad  and 


they  will  be  severely  tested,  and  undesirable 
features  will  be  gradually  eliminated.  The 
advantages  possessed  by  them  in  common  arc 
extreme  simplicity  and  a  high  degree  of  me- 
chanical efficiency.  The  difficulties  that  may 
be  met  are  breaking  down  of  the  armature  from 
vibration,  and  a  very  severe  strain  upon  it 
when  starting  the  motor,  or  mounting  heavv 
grades. 

This  account  of  modern  types  of  motors  for 
electrical  traction  would  be  notably  incomplete 
without  mention  of  the  remarkable  City  and 
South  London  Railway,  inaugurated  in  Novem- 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


299 


ber,  1890,  both  as  the  first  deliberate  attempt 
to  handle  a  large  suburban  traffic  exclusively 
by  electric  locomotives,  and  as  the  first  thor- 
oughly successful  experiment  at  placing  the 
motor  armature  directly  on  the  car  axle. 

As  is  well  known,  the  line  is  an  underground 
one,  and  is  three  miles  in  length,  running  from 
the  heart  of  the  city  of  London,  near  the 
"  Monument,"  beneath  the  Thames,  to  within 
a  mile  of  Clapham  Common.  Including  the 
two  termini  of  the  road,  there  are  along  the 
line  six  stations,  placed  at  about  equi-distant 
points.  The  track  is  double,  and  is  laid  in  two 
separate  steel  tubes,  each  11  feet  in  diameter. 
The  sleepers  are  laid  directly,  without  ballast, 
upon  the  bottom  of  the  tube,  and  the  light 
weight  of  the  rolling  stock  has  made  it  possi- 
ble not  only  to  dispense  with  track  chairs 
altogether,  but  to  use  rails  of  little  more  than 
half  the  usual  weight. 

The  cost  of  the  line  in  round  numbers  has 
been  a  little  more  than  $1,100,000  per  mile. 
Messrs.  Mather  &  Platt,  the  constructors,  have 
guaranteed  that  the  cost  of  motive  power  for 
the  first  two  years  shall  not  exceed  7  cents  per 
train  mile.  As  each  train  is  made  up  of  three 
cars  and  a  locomotive,  and  is  able  to  carry  100 
passengers,  this  compares  very  favorably  with 
the  cost  of  working  the  underground  railway, 
which  expends  20  cents  per  train  mile,  on 
trains  capable  of  carrying  about  450  passen- 
gers, while  its  maintenance  expenses  are  said  to 
be  something  formidable.  Messrs.  Mather  & 
Platt  are  sanguine  that  the  net  efficiency  of 
the  line  will  amount  to  at  least  60  per  cent. 

The  central  generating  station  is  situated  at 
Stockwell,  the  suburban  terminus  of  the  line. 
The  plant  consists  of  three  large  dynamos  of 
the  Edison-Hopkinson  type,  each  worked  inde- 
pendently by  a  vertical  compound  engine, 
designed  and  constructed  by  Messrs.  John 
Fowler  &  Co.  Steam  is  furnished  from  six 
250  horse-power  Lancashire  boilers. 

The  engines  work  at  a  steam  pressure  of  140 
pounds  per  square  inch,  and  are  of  very  mass- 
ive proportions.  They  run  at  100  revolutions 
per  minute,  giving  a  piston  speed  of  450  feet 
per  minute.  They  are  fitted  with  automatic 
expansion  gear  on  both  the  high  and  low  press- 
ure cylinders,  the  governor  being  driven 


direct  from  the  crank  shaft  by  cotton  ropes.   The 
engines  will  indicate  Tip  to  375  horse-power  each. 

The  dynamos  used  embody  the  latest  im- 
provements of  Messrs.  Mather  &  Platt,  and 
are,  as  well  as  the  engines,  built  with  extra 
heavy  parts.  The  weight  of  the  entire  ma- 
chine is  something  over  17  tons,  the  armature 
alone  weighing  about  2  tons,  the  yoke  of  the 
machine  about  3  tons,  and  each  magnet  limb 
with  its  pole  piece,  about  4  tons.  The  capacity 
of  the  machine  is  450  amperes  at  a  pressure  of 
450  volts.  The  commutators  are  of  hard  cop- 
per, insulated  with  mica,  each  rocker  arm 
carrying  three  brushes,  which  are  separably 
adjustable.  The  machines  can  be  run  either  as 
shunt  or  compound,  as  required.  The  total 
weight  of  copper  wire  on  the  magnets  of  each 
machine  is  nearly  one  and  one-half  tons.  The 
machines  are  said  to  have  an  electrical  effi- 
ciency of  96  per  cent.,  or  slightly  more,  and 
the  measured  efficiency  of  the  engine  and 
dynamo,  that  is,  the  ratio  of  the  electrical 
power  available  outside  the  dynamo,  to  the 
indicated  horse-power  of  the  engine,  is  said  to 
be  over  75  per  cent. 

The  current  from  the  dynamo  is  conveyed  to 
a  general  distributing  and  testing  switchboard 
fixed  in  a  recess  of  the  engine  house.  From 
this  board  the  main  circuits  are  taken  to  vari- 
ous parts  of  the  line,  and  the  current  passing 
through  each  circuit  is  measured  by  suitable 
ammeters,  while  arrangements  are  provided  by 
means  of  which  the  current  may  be  switched 
over  from  one  circuit  to  another.  Sir  William 
Thomson's  multicellular  electrostatic  volt- 
meters are  used  for  measuring  the  electro- 
motive force. 

The  working  conductor  is  of  channel  steel, 
carried  on  glass  insulators,  the  joints  being 
fished,  and  also  connected  with  copper  strips. 
The  general  arrangement  of  the  working  con- 
ductor is  exactly  the  same  as  that  employed 
by  Dr.  Edward  Hopkinson  on  the  Bessbrook 
&  Newry  line.  The  steel  employed  is  of  very 
high  conductivity.  The  working  conductor  is 
divided  into  sections  for  convenience  of  testing 
and  the  making  of  necessary  repairs.  When 
the  full  pressure  of  500  volts  is  on  the  com- 
plete system  of  working  and  feeding  conduc- 
tors, the  leakage  current  is  said  to  be  not  more 


300 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


than  one  ampdre,  so  that  the  total  loss  by 
leakage  is  less  than  one  horse-power,  a  small 
fraction  of  one  per  cent,  of  the  total  power  re- 
quired for  working  the  line  to  its  full  capacity. 
The  current  is  collected  from  the  working 
conductor  by  sliding  shoes  of  iron  or  steel 
arranged  much  like  those  employed  on  the 
Bessbrook  line. 

Fourteen   10-ton    electric    locomotives    like 
-that  shown  in  section  in  Fig.  339,  have  been 
supplied  by  Messrs.  Mather  &  Platt  for  work- 
ing the  line,  each  capable  of  developing  100 
effective  horse-power,  and  of  running  up  to  25 


tives  are  fitted  with  Westinghouse  automatic 
air  brakes  and  also  screw  hand  brakes,  and 
they  are  lighted  by  electric  lights,  the  current 
being  derived  from  the  motor  circuit.  The 
train,  when  loaded,  will  weigh  about  30  tons, 
and  it  is  intended  ultimately  that  ten  trains 
shall  be  worked  on  the  line  at  one  time,  these 
being  run  at  three-minute  intervals. 

Up  to  date  the  operation  of  this  unique  road 
has  been  a  complete  success. 

Before  leaving  the  subject  of  motors  for 
electric  traction  some  of  the  minor  but  very 
important  improvements  in  street  railway 


FIG.  339.— ELECTRIC  LOCOMOTIVE  ON  CITY  AND  SOUTH  LONDON  KAILWAY. 


or  26  miles  per  hour.  The  armatures  of  the 
locomotives  are  constructed  so  that  the  shaft 
of  the  armature  is  the  axle  of  the  locomotive ; 
in  this  way  all  intermediate  gear  and  all  recip- 
rocating parts  are  entirely  avoided.  A  motor 
is  fitted  on  each  axle,  as  shown  in  the  cut,  the 
axles  not  being  coupled,  but  working  inde- 
pendently. The  current  is  conveyed  from  the 
collecting  shoes,  through  an  ammeter,  to  a 
regulating  switch,  then  to  a  reversing  switch, 
thence  to  the  motors  and  back  through  the 
framework  of  the  locomotive  to  the  rails,  so 
completing  the  electrical  circuit.  The  locomo- 


practice  are  well  worth  mentioning.  Perhaps 
the  most  valuable  single  advance  in  apparatus 
has  been  the  introduction  of  the  carbon  brush 
for  railway  motors.  This  improvement  really 
made  the  difference  between  the  success  and 
failure  of  the  electric  street  car.  It  was  of 
course  quite  practicable  to  operate  motors  with 
copper  brushes,  but  they  were  continually 
turning  when  the  motors  were  reversed,  and 
were  a  never-ceasing  source  of  delay,  annoy- 
ance and  vexation  to  the  car  operators  and  to 
the  public.  The  present  carbon  brush  is  a 
mere  bar,  closely  lesembling  electric  light  car- 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


301 


bon.  It  is  in  general  from  two  to  three  inches 
wide  by  a,  quarter  to  one-half  inch  thick  and 
from  two  to  three  inches  long.  It  is  usually 
copper-plated,  and  held  by  spring  pressure  in 
a  simple  holder  radially  against  the  commuta- 
tor. It  gives  an  excellent  contact,  very  sel- 
dom breaks,  stands  reversal  of  the  armature 
direction  without  causing  the  slightest  trouble, 
and  never  needs  trimming  unless  accidentally 
nicked.  Sparking  is  reduced  to  a  very  small 
amount  by  this  device  if  the  commutator  is 
kept  anywhere  nearly  clean.  Its  only  disad- 
vantage is  the  free  way  in  which  it  distributes 
small  particles  of  carbon  during  the  progress  of 
wearing.  With  proper  care,  however,  it  simply 
forms  a  dark  glaze  over  the  surface  of  the  com- 
mutator without  either  short-circuiting  the 
sections  or  causing  any  tendency  to  sparking. 
If,  however,  the  commutator  is  allowed  to  get 
dirty  and  accumulate  carbon  dust,  there  is  im- 
mediate trouble  from  the  commutator  heating 
through  short  circuiting,  and  also  from  the 
tendency  of  sparks  to  flash  around  the  com- 
mutator in  the  conducting  layer  thus  formed. 
With  a  reasonable  amount  of  care  no  trouble 
of  this  kind  need  be  experienced. 

Another  source  of  great  difficulty  that  has 
been  partially  eliminated  at  the  present  time 
is  the  trolley  that  collects  current  from  the 
working  conductor.  The  main  trouble  in  this 
case  comes  not  from  the  trolley  wheel  proper 
but  from  the  difficulty  of  getting  a  smooth  up- 
ward pressure  by  springs  without  the  danger 
of  frequent  breakage.  The  early  trolleys  were 
continually  getting  out  of  order ;  the  wheels 
would  get  jammed  and  refuse  to  turn ;  their 
bearings  would  give  way,  and  occasionally  the 
trolley  and  pole  would  come  down  together 
into  the  street  with  a  crash.  The  principal 
difficulty  with  the  wheel  is  due  to  the  imprac- 
ticability of  using  much  lubrication,  and  a 
long  series  of  experiments  was  necessary  be- 
fore any  ways  were  found  of  constructing 
bearings  which  should  give  good  conduction 
for  the  current,  and  at  the  same  time  good 
mechanical  properties.  By  the  free  use  of 
anti-friction  material  and  more  careful  work- 
manship this  difficulty  has  been  largely  elim- 
inated. Experience,  too,  has  taught  ways  of 
giving  a  spring  pressure  to  force  the  trolley 


pole  upward  against  the  trolley  wire  without 
continual  breakage.  This  perhaps  has  been 
best  attained  by  the  use  of  spiral  springs 
strictly  in  tension.  Very  recently  aluminium 
has  been  occasionally  substituted  for  brass  and 
bronze  as  the  material  for  the  trolley  wheel 
and  its  immediate  support.  The  result  of  this 
is  very  much  to  reduce  the  weight  that  has  to 
be  held  against  the  trolley  wire  and  thus  sim- 
plify the  mechanical  process  of  obtaining  even 
pressure.  With  a  trolley  wire  properly  lined 
tip  a  continuous  contact  is  the  rule  and  only 
rarely  does  the  collector  jump  from  the  wire. 
Some  experiments  have  been  tried  with  sliding 
contacts  instead  of  wheels,  with  a  fair  degree 
of  success. 

In  line  construction  a  vast  number  of  clever 
and  ingenious  devices  for  facilitating  various 
portions  of  the  work  have  been  introduced. 
The  substitution  of  iron  for  wooden  support- 
ing poles  for  the  trolley  line  has  been  a  very 
great  advantage,  as  it  enables  the  line  to  be 
kept  taut  and  true  without  the  continual 
annoyance  from  sagging  that  was  the  experi- 
ence of  a  couple  of  years  ago.  The  general  con- 
struction of  electric  railway  lines  is  steadily 
improving  and  consequently  the  electric  motor 
is  more  thoroughly  appreciated.  Most  of  the 
difficulties  that  have  to  be  met  are  mechanical 
ones,  and  when  it  was  thought  practicable  to 
operate  heavy  motor  cars  on  old  horse-car 
tracks  with  light  rails  on  lighter  stringers, 
trouble  of  every  kind  was  incessant.  But  now 
that  engineers  have  come  to  appreciate  the  im- 
portance of  solid  track  construction  and  careful 
line  work  the  motors  are  found  to  perform  bet- 
ter than  was  ever  supposed  possible. 

During  the  last  two  years  underground  and 
storage  battery  systems  of  supply  have  re- 
mained practically  at  a  standstill.  The  former 
is  not  now  in  use  except  in  an  experimental 
way  in  the  United  States,  although  some  of 
the  foreign  roads  have  met  with  success.  A 
steady  effort  has  been  made  to  bring  the  stor- 
age battery  to  the  front  but  the  inherent  diffi- 
culties have  proved  too  much  for  it.  It  has 
been  tried  thoroughly  and  carefully,  but  with 
very  indifferent  success.  Two  years'  experience 
in  Philadelphia  with  half  a  dozen  cars  in  active 
service  has  led  to  the  abandonment  of  the 


302 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


scheme.  Two  years'  trial  on  a  considerable 
scale  in  New  Orleans  has  just  terminated  in  a 
similar  failure.  Cars  have  been  running  spas- 
modically on  the  Fourth  Avenue  line  in  New 
York,  with  fair  success,  when  they  have  been 
operated  at  all,  but  nothing  has  come  of  it. 
There  is  a  single  small  storage  battery  road  in 
Massachusetts;  a  few  cars  in  Dubuque,  la.,  a 
few  in  Washington,  and  scattered  experimental 
cars  here  and  there.  That  is  all  that  has  come 
of  the  storage  battery  so  far.  The  case  is  by 
no  means  a  hopeless  one,  however,  and  there 
is  every  reason  to  believe  that  eventually  the 
storage  battery  may  take  a  prominent  part  in 
city  electrical  traction.  Up  to  the  present  then 
there  is  very  little  to  report.  One  promising 
series  of  experiments,  however,  was  recently 
carried  out  in  Philadelphia  with  the  Waddell- 
Entz  storage  battery,  a  modification  of  the 
alkaline  zincate  type.  To  sum  it  all  up,  stor- 
age battery  traction  may  be  a  success  but  it 
generally  is  not. 

Of  stationary  motors  there  has  been  little 
less  than  a  deluge  during  the  two  years  since 
the  second  edition  of  this  book  was  published. 
Some  of  this  numerous  list  of  machines  have 
interesting  and  useful  peculiarities ;  others  are 
simply  imitations  of  some  well-known  type,  or 
designed  with  more  or  less  skill  on  general 
principles,  but  without  possessing  any  strik- 
ing merits  or  demerits.  Within  the  scope  of 
this  volume  it  is  simply  out  of  the  question  to 
describe,  or  even  mention,  the  majority  of  the 
stationary  motors  that  are  on  the  market. 
Most  of  them  are  good  ;  the  general  character 
of  their  designs  follows  a  comparatively  small 
number  of  models,  and  the  running  speed, 
efficiency,  and  price  are  for  the  most  part  not 
widely  different.  Hence,  in  the  brief  space 
that  must  necessarily  be  allotted  to  descrip- 
tion, no  attempt  will  be  made  at'  completeness, 
but  a  few  characteristic  machines  that  are  in 
especially  wide  use,  or  that  possess  some  pecu- 
liarly interesting  features  of  design  or  con- 
struction, will  be  described.  For  the  further 
information  of  those  who  desire  details  of  par- 
ticular machines,  we  can  do  no  better  than  to 
refer  them  to  the  current  tiles  of  THE  Eu:c- 
TKICAL  WORLD,  wherein  new  motors  are  gen- 
erally described  very  soon  after  their  appear- 


ance before  the  public.  As  this  chapter  is  not 
intended  for  a  catalogue  of  all  known  ma- 
chines, but  for  the  intelligent  information  of 
those  who  desire  to  make  themselves  acquaint- 
ed with  good  modern  practice,  attention  will 
be  confined  to  a  limited  number  of  thoroughly 
well-known  and  practical  machine^. 

A  couple  of  years  ago  the  Sprague  station- 
ary motor  was  the  best  known  machine  of  its 
class,  and  continued  a  general  favorite  up  to 
the  time  that  the  Sprague  Company  was  swal- 
lowed up  by  the  Edison  General  Electric  Com- 
pany. The  Sprague  type  was  then  immediately 


FlG.  340. — TWENTY-FTVF.  KlI.O-W ATT  ElHRON  MOTOR. 

and  completely  discarded,  and  in  its  place  was 
put  the  Edison  motor,  that  is  at  once  an  ex- 
cellent specimen  of  modern  design  and  a  capi- 
tal lesson  in  the  reversibility  of  the  dynamo. 
It  is  nothing  more  nor  less  than  the  well- 
known  and  reliable  Edison  dynamo,  operated 
as  a  motor,  with  merely  such  changes  as  are 
necessary  in  reversing  the  direction  of  rotation 
of  the  armature.  The  differences  between  it 
and  the  incandescent  dynamo  of  a  similar  size 
are  scarcely  discernible,  and  the  windings  are 
practically  identical,  except  in  the  machines 
designed  for  special  purposes.  This  is  a  suffi- 
cient commendation,  for  it  is  needless  to  say 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888! 


303 


that  the  same  characteristics  that  make  a  good 
and  reliable  dynamo  are  sufficient  to  ensure 
admirable  performance  in  a  motor.  Fig.  340 
shows  the  complete  machine.  The  type  and 
general  appearance  remain  the  same  from  the 
smallest  motor  manufactured,  that  of  J  horse- 


EDISON 
STANDARD    MOTOR 


AUTOMATIC 
STARTING 
RHEOSTAT 


FIG.  341.— CONNECTIONS  OF  EDISON  MOTOB. 

power,  up  to  the  150  horse-power  motor,  cor- 
responding to  the  largest  of  Edison  dynamos. 
Fig.  341  shows  the  diagram  of  connections, 
both  of  the  motor  itself  and  of  the  rheostat, 
while  Fig.  342  gives  a  view  of  the  self-oiling 


FIG.  342.— EDISON  SELF  OILING  BEARIKG. 

bearing  that  is  one  of  the  most  desirable 
mechanical  features  of  the  machine.  This  de- 
vice insures  complete  and  excellent  lubrication 
for  long  periods  of  running.  The  brushes 
usually  employed  with  these  motors  are  of  the 


regular  Edison  type  and  are  of  hard,  straight, 
copper  wires  ;  occasionally  they  are  replaced 
by  carbon  brushes. 

The  machines  are  made  of  all  sizes,  the 
smaller  ones  generally  being  intended  for  110 
volts,  and  the  larger  sizes  for  220  or  500  volts. 
For  these  higher  voltages  of  course  the  wind- 
ings are  special,  but  the  dimensions  and  the  ar- 
rangements of  the  machines  remain  practically 
the  same.  The  speed  of  the  motors  is  very 
nearly  that  of  the  corresponding  sizes  of  dyna- 
mo of  the  same  voltage,  and  ranges  from  2,100 
revolutions  per  minute  in  the  £  and  4  horse- 
power motors  to  as  low  as  300  in  the  150  horse- 
power machine,  the  largest  one  listed.  The  Edi- 


FIG.  343. — DETAIL  VIEW  OF  CROCKER- WHEELER 
MOTOR. 

son  Company  makes  at  present  only  constant 
potential  machines,  using  for  constant  current 
work  mainly  the  excellent  constant  current 
motor  manufactured  by  the  Crocker- Wheeler 
Motor  Co.,  whose  machines  are  very  widely 
known,  and  are  of  special  interest  as  displaying 
a  design  and  construction  peculiarly  their  own 
and  quite  apart  from  ordinary  dynamo  types. 

Fig.  343  gives  an  excellent  detailed  view  of 
the  standard  Crocker- Wheeler  motor,  while 
Fig.  344  shows  the  general  appearance  of  the 
5  horse-power  pattern.  To  begin  with,  the 
machine  is  of  the  inverted  horseshoe  type;  each 
pole  piece  is  continuous  with  its  magnetic  core, 


304 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


and  is  formed  of  the  softest  iron,  drop-forged 
exactly  to  its  finished  shape.  These  forgings 
are  fitted  very  carefully  into  recesses  in  the 
main  casting  of  the  motor  that  forms  at  once 
the  magnet  yoke  and  the  support  for  the  bear- 


small  that  the  magnetic  resistance  of  the  air  gap 
is  exceptionally  low,  and  the  coils,  sunk  flush 
with  the  surface  of  the  armature,  are  subjected 
to  a  very  powerful  induction.  This  construc- 
tion, too,  gives  almost  complete  immunity 
from  burning  out  of  the  armature,  as  each, 
section  is  isolated,  and  no  two  contiguous 
wires  are  subjected  to  any  considerable  dif- 
ference of  potential.  Relatively  large  as  the 
armatures  are  they  are  yet  exquisitely  bal- 
anced, and  run  almost  without  vibration, 
while  the  size  gives  a  powerful  torque  and 
good  efficiency  at  an  unusually  low  speed, 
exceptionally  low  for  a  two-pole  machine. 
The  bearings,  shown  in  detail  in  Fig.  345, 
have  all  the  mechanical  features  of  those  em- 
ployed in  the  largest  machines,  are  self-oiling 
and  self  centering.  Both  constant  potential 
and  constant  current  motors  are  made  by  the 
Crocker- Wheeler  Company,  and  in  general 
appearance  closely  resemble  each  other. 


FIG.  344. — FIVE  HOUSE-POWER  CROCKER- WHEELER 
MOTOR. 

ings.  The  armature  is  relatively  of  very  large 
diameter,  and,  compared  to  the  field,  quite 
powerful.  •  The  pole  pieces  are  rather  lean  in 
figure,  but  their  lack  of  cross-section  is  more 
than  compensated  by  the  excellent  quality 


FIG.  345. — CROCKER-WHEELER  SELF  OILING 
BEARING. 

of  the  iron.  The  result  of  this  construction  is 
;i  very  powerful  field  obtained  most  econom- 
ically. The  armature  is  a  Pacinotti  ring  with 
a  comparatively  small  amount  of  wire  wound 
upon  it.  The  clearance  of  the  armature  is  so 


FIG.  346. — CROCKER-WHEELER  FAN  MOTOR. 

It  is  the  intention  of  the  makers  that  the 
smallest  machine  turned  out  shall  be  as  com- 
plete and  perfect  in  all  its  details  as  the  largest. 
A  glance  at  the  machine,  Fig.  346,  shows  an- 
other excellent  mechanical  feature,  for  the 
supports  of  the  bearings  are  fitted  to  the  pro- 
jecting base  of  the  machine  that  carries  them, 
not  with  a  straight  joint,  but  with  a  bearing 
that  follows  the  arc  of  a  circle,  so  that  in 
taking  out  the  armature  and  replacing  it  again 
there  is  no  danger  of  getting  it  in  the  least  out 
of  line.  Fig.  344,  the  5  horse-power  motor,  is 
the  largest  size  regularly  made,  and  from  that 
the  motors  run  down  to  the  little  -  horse- 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


305 


power  affair  principally  used  in  driving  fans. 
All  the  sizes  retain  the  same  fundamental 
characteristics.  The  little  fan  motor  just  men- 
tioned is  shown  in  Fig.  346.  It  carries,  usually, 
a  12-inch  fan,  and  has  come  into  very  exten- 
sive use  in  offices,  restaurants,  and  the  like. 


FIELD  COILS 

FIG.  347. — CROCKER-WHEELER  STARTING  SWITCH. 

On  its  pole  piece  will  be  noticed  a  starting 
switch,  which  is  supplied  to  all  the  small  mo- 
tors for  starting  and  stopping,  and  in  some 
cases  for  regulating.  This  switch  when  turned 
first  charges  the  field,  then  starts  the  armature 
through  a  resistance  wound  on  the  machine, 
and  finally  cuts  out  the  resistance  and  gives 
the  fxill  current  to  the  armature.  The  details 
of  this  little  device  are  well  shown  in  Fig.  347. 
The  constant  potential  motors  are  wound  for 
almost  every  possible  case,  for  voltages  from 
6  volts,  for  use  with  a  battery,  to  500  volts,  to 
be  employed  on  a  railway  circuit.  The  battery 
motors  are  usually,  however,  series  wound. 
The  sizes  up  to  £  horse-power  may  be  pro- 
vided with  a  starting  device  employing  a  two- 
speed  switch  for  use  if  occasion  requires,  and 
motors  of  all  the  usual  sizes  and  voltages  are 
arranged  with  reversible  switches,  if  desired. 
Regulating  boxes  similar  to  those  used  with 
the  Edison  motors  furnish  means  for  varying 
the  speed  of  the  larger  sizes.  Besides  these 
constant  potential  machines,  the  Crocker- 
Wheeler  Company  makes  a  large  number  of 


motors  for  constant  current,  to  be  employed 
where  arc  circuits  only  are  available.  A  com- 
plete series  of  these  machines  is  made,  ranging 
from  £  horse- power  xip  to  5  horse  power,  and 
meet  wide  use  where  incandescent  circuits 
are  not  within  reach.  They  are  in  general  ap- 
pearance very  similar  to  the  constant  potential 
machines.  In  the  latest  models  regulation  is 
accomplished  by  shifting  the  brushes.  This 
movement  in  the  larger  motors  is  accomplished 
by  a  centrifugal  governor  acting  upon  the 
brush  holders. 

Fig.  348  shows  one  of  the  smaller  constant 
current  motors.  They  are  wound  regularly  for 
6£,  9£,  or  18  ampere  circuits.  The  arc  motors 
below  £  horse-power  are  fitted  with  a  simple 
hand-governor  instead  of  the  centrifugal  ar 
rangement,  for  they  are  generally  used  only 
on  regular  wrork,  for  which  they  may  be  set  to 
run  at  any  desired  speed. 

It  will  thus  be  seen  that  the  Crocker- Wheeler 
machines  are  characteristically  motors  in  con 
struction,  having  an  armature  vastly  more 
powerful  than  is  usual  in  dynamos,  and  being 
intended  to  give  a  powerful  torque  and  low 
speed.  Nevertheless,  the  larger  sizes  of  con- 
stant potential  machines  are  not  infrequently 
used  for  dynamos,  and  work  admirably  for  this 


FIG.  348. — SMALL  CROCKER- WHEELER  CONSTANT 
CURRENT  MOTOR. 

purpose.  They  may  be  said  to  represent,  how- 
ever, the  motor  type,  just  as  the  Edison  motor 
is  the  typical  reversible  dynamo. 

To  the  latter  category  belongs  another  mod- 
ern motor  that  is  mentioned  here  especially  on 
account  of  the  character  of  its  magnetic  circuit. 


3pG 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


The  Connecticut  motor,  which  for  the  past 
two  years  has  been  manufactured  at -Plants- 
ville,  Conn.,  is  almost  unique  from  the  fact 
that  throughout  all  sizes  of  the  machine  the 
magnetic  circuit  is  composed  of  a  single  cast- 
ing without  joints  of  any  kind.  It  was  de- 
signed especially  with  the  idea  of  furnishing 


FIG.  349. — THE  CONNECTICUT  MOTOR. 

a  simple,  strong  and  reliable  motor  of  fair 
efficiency  and  good  mechanical  qualities.  There 
has  been  a  certain  tendency  in  electrical  ma- 
chine design  to  fly  to  one  of  two  extremes, 
either  to  build  a  motor  exceedingly  efficient 
but  somewhat  thin-skinned  and  unable  to  re- 
sist severe  strains,  or,  on  the  other  hand,  to 
neglect  electrical  efficiency  too  much.  The 
present  Connecticut  motor  is  of  a  compromise 
pattern,  and  while  remarkably  simple  in  con- 
struction has  a  good  efficiency  and  is  mechan- 
ically well  made.  The  form  of  the  machine 
throughout  is  the  inverted  horseshoe.  In  the 
smaller  sizes  the  armature  is  supported  by 
brackets  fastened  to  the  pole  pieces  ;  in  the 
larger  sizes  by  bearings  carried  on  an  extension 
of  the  base. 

Fig.  349  shows  the  first  pattern,  which  is 
adapted  for  machines  of  2  horse-power  and 
under.  The  magnetic  circuit  is  short  and 
its  cross-section  large ;  it  is  a  single  cast- 
ing of  soft  iron,  so  formed  that  the  mag- 
netizing coils  can  be  wound  on  bobbins  and 
dropped  directly  over  the  pole  pieces.  The 
armature  is  a  drum  about  two  diameters  long, 
wound  with  a  comparatively  small  number  of 
turns,  and  with  rather  coarse  wire.  The  air 


gap  is  short  and  the  magnetizing  power  re- 
quired, owing  to  this  fact  and  to  the  absence  of 
any  joints,  is  very  small  for  a  cast  iron  magnet. 
The  smaller  sizes  have  the  shaft  revolving  in 
graphite  bushings,  while  the  larger  ones  are 
provided  with  self-oiling  bearings.  In  all  the 
journals  are  allowed  a  large  bearing  surface. 
The  machines  are  manufactured  for  incandes- 
cent circuits  only,  and  are  shunt  wound  for 
110,  220  and  600  volts.  They  are  started 
through  the  medium  of  a  switch  box  not  un- 
like that  employed  in  the  Edison  and  several 
other  systems.  Generators  of  the  same  form 
are  also  manufactured,  being  either  shunt  or 
compound  wound,  as  the  occasion  requires. 

Another  very  well  known  electric  motor  is 
the  Eddy,  which  like  the  Edison  and  Connecti- 
cut motors  follows  the  usual  lines  of  dynamo 
construction  very  closely.  The  magnetic  cir- 
cuit is  of  a  modified  horseshoe  form,  somewhat 
elliptical  in  shape,  and  of  large  cross-section, 
and  it  is  usually  mounted  on  a  wooden  base. 
The  material  is  soft  cast  iron,  and  the  motor  is 
shunt  wound  with  unusually  fine  wire.  The 
armature  is  of  the  drum  form,  Siemens  wound, 
as  usual.  It  is  wound  with  a  comparatively 
small  number  of  turns  of  rather  coarse  wire, 


FIG.  350. — THE  EIJDY  MOTOR. 

giving  a  low  armature  resistance.  All  motors 
of  above  7^  horse-power  are  wound  with  several 
wires  in  parallel  for  convenience  and  efficiency. 
The  armature  is  supported  by  gun-metal  yokes 
fastened  rigidly  to  the  pole  pieces  of  the  mag- 
net by  gun-metal  studs.  These  yokes  contain 
bearing  sleeves  of  hard  composition  metal. 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


307 


The  bearings  of  all  sizes  are  self-oiling  and 
consequently  require  but  little  attention.  The 
self -oiling  device  is  a  loose  ring  hanging  on  the 
shaft  and  dipping  into  an  oil  well,  the  form 
employed,  with  various  modifications,  on  nearly 
every  self-oiling  bearing.  After  the  oil  works 
along  the  shaft  it  comes  out  at  each  end  of  the 
box,  is  caught  in  grooves  turned  for  that  pur- 
pose, and  immediately  returns  to  the  well.  The 
regulation,  as  might  be  expected  from  the  de- 
sign, is  automatic,  and  the  machines  have 
given  an  excellent  account  of  themselves  in  a 
wide  variety  of  service.  They  are  manufac- 
tured in  all  sizes  and  for  all  the  usual  voltages. 
Fig.  350  gives  a  good 
idea  of  the  motor  in 
question. 

A  very  compact  and 
well  worked  out  de- 
sign may  be  found  in 
the  motors  recently 
brought  out  by  the 
United  States  Electric 
Lighting  Co.  They 
present  a  radical  de- 
parture from  the 
usual  shapes  of  mag- 
netic circuit,  the  form 
presented  requiring 
but  a  single  magnetiz- 
ing coil,  and  being  vir- 
tually an  inverted 
horseshoe  in  shape, 
with  the  coils  wound 
around  the  yoke,  as 
shown  in  Fig.  351. 
The  magnetic  circuit 
is  cast  in  two  pieces, 
the  joint  being  in  the  center  of  the  magnetiz- 
ing coil,  and  the  two  portions  being  held  to- 
gether by  the  bolts  shown  in  the  cut.  The 
mechanical  construction  is  exceedingly  sim- 
ple, as  the  field  magnets  iorm  their  own  base 
by  projections  cast  solid  with  them,  and  sim- 
ilar projections  form  a  support  lor  the  bear- 
ings of  the  armature  shaft.  The  switch  lor 
controlling  the  motor  is  placed  directly  on 
top  of  the  pole  pieces.  These  motors  are  made 
in  sizes  from  $  horse-power  up  to  20  horse- 
power, wound  for  all  the  usual  potentials  up 


FIG.  351.— THE  UNITED  STATES  MOTOR. 


to  500  volts.  The  armature  presents  some  in- 
teresting peculiarities ;  it  is  a  drum  of  rather 
large  diameter,  and  is  of  the  toothed  variety ; 
the  teeth  are  very  numerous  and  small,  so  that 
no  trouble  is  encountered  from  the  heating  that 
almost  always  follows  the  use  of  large  projec- 
tions in  an  armature.  This  construction  ac- 
complishes two  ends  in  the  most  admirable 
fashion.  In  the  first  place  it  reduces  the  air 
gap  to  a  very  minute  amount,  inasmuch  as  the 
teeth  run  very  close  to  the  polar  surfaces.  In 
the  second  place  it  simplifies  winding  the  ar- 
mature immensely,  for  no  special  care  need  be 
taken  in  laying  off  the  various  sections  as  the 

armature  is  wound ;  it 
is  simply  necessary  to 
take  the  size  of  wire 
used  for  that  particu- 
lar motor  and  fill  the 
space  between  the 
teeth  with  it,  thus 
forming  an  independ- 
ent segment  of  the 
armature.  The  me- 
chanical advantage  se- 
cured by  this  con- 
struction is  that  all 
the  armature  wires 
and  bands  lie  beneath 
the  surface  of  the  ar- 
mature and  are  there- 
fore completely  pro- 
tected from  injury. 
The  armature  resis- 
tance is  very  low,  and 
the  field  secured  by 
the  compact  Iorm  of 
magnetic  circuit  is  a 
very  powerful  one,  so  that  the  efficiency  of 
the  finished  motor  is  high,  and  its  speed  mod- 
erate. By  careful  design  ot  the  pole  pieces 
the  non-sparking  area  is  sufficiently  increased 
lor  the  motors  to  run  without  shifting  the 
brushes,  even  under  very  violent  changes 
of  load.  Sizes  of  1  horse-power  and  above 
are  supplied  with  a  special  base  and  belt- 
tightener  when  necessary.  Like  the  other 
motors  just  mentioned,  these  are  constant  po- 
tential machines,  and  are  frequently  used 
as  dynamos,  making  a  very  compact  and 


308 


THE  ELECTRIC  MOTOR  AND  ITS  APPLICATIONS. 


efficient  machine  for  generating  purposes. 
When  used  as  dynamos  they  are  very  often 
compound  wound.  For  a  motor  to  be  used 
for  potentials  above  220  volts  a  special  start- 
ing device  is  employed,  enclosed  in-  a  glass- 
topped  case,  so  that  accidental  contact  with 
the  terminals  of  the  machine  is  impossible. 
For  these  high  potential  forms  the  brushes  are 
held  in  hard  rubber  brush-holders  lined  with 
metal,  so  constructed  as  to  avoid  the  danger  of 
receiving  shocks  from  either  brush  or  holder. 

A  group  of  machines  that  possess  some  ex- 
cellent features,  and  have  served  as  a  model 
for  not  a  few  imitations,  are  the  Ferret  motors 
made  by  the  Elektron  Manufacturing  Com- 
pany of  Brooklyn.  Their  distinctive  feature 
is  the  lamination  of  the  field  magnet ;  instead 
of  being  cast  or  forged  in  one  or  more  solid 
pieces,  as  usual,  it  is  built  up  of  thin  plates  of 
charcoal  iron  stamped  into  their  finished  form, 
and  then  clamped  together  by  bolts.  The  ad- 
vantage of  such  a  construction  is  primarily  the 
ready  use  of  the  best  quality  of  soft  iron  for 
the  magnetic  circuit.  The  lamination  further 
tends  to  check  eddy  currents  in  the  pole  pieces, 
and  enables  the  toothed  armature  to  be  used 
without  any  special  difficulties  from  the  cause 
just  mentioned.  At  first  sight  the  laminated 
magnets  might  appear  costly,  but  the  simplic- 
ity of  construction  by  stamping  has  in  large 
part  obviated  this  objection.  The  armatures 
are  provided  with  teeth,  and  the  coils  wound 
in  the  spaces  between  them  are  completely  be- 
neath the  surface  of  the  armature,  and  thor- 
oughly protected  from  injury.  The  toothed 
construction,  as  mentioned  in  describing  the 
United  States  motor,  enables  the  air  gap  to  be 
reduced  to  a  very  small  amount,  consequently 
the  magnetism  is  very  economically  obtained, 
and  the  armature  wire  is  utilized  to  the  best 
advantage.  The  Elektron  Company  does  not 
confine  itself  to  a  single  type  of  machine,  but 
manufactures  three  distinct  patterns.  The 
first,  used  for  the  smallest  sizes  ot  motors, 
is  of  the  erect  horseshoe  form,  and  is  pro- 
vided with  a  toothed  drum  armature.  For 
somewhat  larger  motors,  up  to  2  horse-power, 
the  consequent  pole  form  of  magnetic  cir- 
cuit with  four  magnetizing  coils  is  employed  ; 
while  for  larger  machines  the  two-pole  con- 


struction is  abandoned  and  the  Ferret  mo- 
tors from  2  to  20  horse-power  are  six-pole 
machines  with  ring  armatures.  The  special 
advantage  to  be  gained  by  the  multipolar  con- 
struction is  light  weight  and  low  speed  for  a 
given  efficiency  and  output.  The  modern  ten- 
dency in  motor  building  is  toward  lowering 
the  running  speed  as  far  as  possible,  because 
for  most  purposes  for  which  small  motors  are 
used  a  speed  of  1,500  to  2,000  revolutions  per 
minute  is  far  higher  than  is  desirable  in  the 
machines  that  are  to  be  driven,  consequently  the 
speed  must  be  reduced  by  belting  or  gearing  in 
a  very  considerable  ratio  ;  so  much,  in  fact,  as 
to  cause  the  loss  of  considerable  power  through 


FIG.  352. — PERKET  MULTIPOLAR  MOTOR. 

countershafts.  The  more  nearly  the  speed  of 
any  motor  can  be  made  to  correspond  with  the 
driven  machine  the  more  economically  it  can 
be  applied,  so  that  there  is  a  very  great  advan- 
tage in  the  use  of  the  multipolar  construction 
with  its  consequent  reduction  of  speed.  In 
these  larger  Ferret  motors  the  laminated  field 
magnets  are  retained.  Fig.  352  shows  one  of 
the  latest  multipolar  motors  of  5  horse-power. 
Fig.  353  exhibits  the  arrangement  of  the  mag- 
netic circuit.  The  six  poles  are  furnished  with 
three  independent  magnets  arranged  at  equi- 
distant points  around  the  armature.  There  are 
but  three  magnetizing  coils,  each  one  energiz- 


DEVELOPMENT  OF  THE  ELECTRIC  MOTOR  SINCE  1888. 


300 


ing  a  single  magnet.  There  are  no  joints  at  all 
in  the  magnetic  circuit  except  the  air  gap, 
since  the  stampings  that  form  the  individual 
magnets  are  of  such  shape  that  they  can  be 
readily  wound  in  a  lathe.  The  armature  is  a 
ring  of  relatively  very  large  diameter,  toothed, 


FIG.  353. — MAGNETIC  CIRCUIT  OP  FERRET  MULTI- 

I'OLAK   MoTOK. 

and  running  very  close  to  the  pole  pieces  as  in 
the  usual  forms  of  the  Ferret  motor.  The  re- 
sulting machine  is  a  very  compact,  convenient 
and  efficient  one,  and  its  speed  is  singularly 
low,  only  about  half  that  employed  in  two-pole 
motors  of  corresponding  size.  The  very  small 


sizes  have  come  into  wide  use  for  fans,  sewing 
machines  and  the  like  ;  while  the  larger  ones 
recently  introduced  have  made  a  good  reputa- 
tion for  ordinary  power  purposes. 

A  large  number  of  electric  motors  besides 
those  mentioned  have  been  placed  upon  the 
market  within  the  past  two  years.  Most  of 
them  have  no  special  distinguishing  peculiari- 
ties that  are  not  well  shown  in  one  or  more  of 
the  motors  that  have  just  been  described.  They 
represent  individual  experience  and  fancy  in 
electrical  design,  and  are  most  of  them  of  good 
quality.  There  is  to-day  no  excuse  for  build- 
ing a  poor  motor. 

Of  alternating  current  motors  there  is  com- 
paratively little  to  be  said.  A  large  number 
of  patents  have  been  taken  out,  there  has  been 
much  interesting  discussion  as  to  details  of 
construction,  but  very  few  motors  have  been 
built  and  fewer  yet  sold.  None,  at  the  time 
of  writing,  have  been  used  extensively  enough 
to  enable  a  judgment  to  be  formed  as  to  their 
practical  qualities.  The  Tesla  machines,  men- 
tioned in  Chapter  XV,  are  perhaps  the  best 
known  of  any,  but  even  they  have  not  come 
into  any  considerable  use.  Very  little  that  is 
radically  new  has  been  done  in  alternating  cur- 
rent construction,  and  the  present  state  of  the 
art  is  effectively  covered  by  the  chapter  just 
mentioned. 


PACK 

Adams  on  Alternate-Current  Motors       .         .  255 
Alternate  Currents  : 

Adams     .......  255 

Duncan,  L 262 

Ferraris 271 

Hopkinson       .         .         .         .         .    '     .  255 

Patten 260 

Tesla 264 

Thomson,  E .256 

Wilde 255 

"Ampere,"  The 70 

Antwerp  Tests  of  Tramway  Motors,  The        .  104 

Antwerp  Electric  Kail  way,  The  (Storage)       .  104 

A  very  Motor,  The  .         .         .         .         .         .  17 

Ayrton-Perry  Motor,  The       ....  122 

Balloon,  Krebs-Renard,  The  ....  140 

Balloon,  Tissandier.  The        ....  138 

Baltimore  Electric  Railway,  The    ...  73 

Baltimore  Electric  Railway,  The  (Storage)     .  108 

Baxter  Motor,  The          ...                  .  227 

Baxter  Slow  Speed  Railway  Motor           .         .  290 

Beattie  Motor,  The 153 

"Benjamin  Franklin,"  The   ....  78 

Beutley-Knight  Electric  Railway,  The   .         .  81 

Bentley-Knight  Large  Locomotive          .         .  83 

Bentley-Knight  Woonsocket  Road          .         .  200 

Bentley-Knight  Allegheny  City  Road      .         .  201 

Berlin  Electric  Railway,  The          ...  48 

Berlin  Electric  Railway,  The  (Storage)  .         .  103 

Berliner  Pyromagnetic  Generator  .         .         .  278 

Besspool  Electric  Railway,  The      ...  59 

Blackpool  Electric  Railway,  The    ...  55 

Blower  with  Daft  Motor          .                  .         .  129 

Botto  Motor,  The 8 

Bourbouze  Motor,  The   .         .         .         .         .  n 

Breuil-en-Auge  Electric  Railway,  The    .         .  100 

Brighton  Electric  Railway,  The      ...  55 

Brown  Motor,  The  (Oerlikon)         .         .         .  251 

Brush  Motor,  The  ....  154 


PAGE 

C.  &  C.  Motor,  The 230 

Calking-Machine,  The  Rowan         .         .         .  250 

Card  Motor,  The 242 

Chandler  Telpher  System,  The       .         .         .148 

Chicago  Electric  Railway,  The        ...  62 

Cleveland  Electric  Railway,  The    ...  81 

Clipping-Machine,  The  Rowan        .         .         .  250 

Conductor,  Rae,  T.  W.,  on  Size  of  the   .         .  44 

Conductor,  Thomson,  Sir  W.,  on  Size  of        .  47 

Coney  Island  Electric  Railway,  The        .         .  73 

Connecticut  Motor,  The         ....  306 

Cook  Motor,  The    .        .        .         .         .         .  15 

Crocker-Wheeler  Motor,  The           .         .         .  303 
Curtis  &  Crocker  Motor,  The          .         .         .155 

Daft  Motor,  The 127 

Daft  Motor  "  Benjamin  Franklin,"  The         .  78 

Daft  Motor  "Ampere,"  The   ....  70 

Daft  Electric  Railway,  The    ....  70 

Daft  Motor  with  Blower          ....  129 

Davenport  Motor,  The   .....  13 

Davidson  Motor,  The      .         .         .         »         .  9 

De  Morat  Motor,  The     .         .  26 

Deprez  Generator,  The  .....  41 

Deprez  Generator  at  Creil,  The      ...  41 

Deprez  Motor,  The         .....  115 

Dichl  Motor,  The 133 

Diehl  Motor  and  Sewing-Machine,  The           .  244 

Dover-Calais  Voyage  of  the  "  Volta,"  The      .  138 

Drill,  Taverdon,  with  Gramme  Motor,  The    .  121 

Drilling-Machine,  The  Rowan         .         .         .  249 
Drybrook  Mine  Electric  Railway,  The  (Storage)    110 

Du  Moncel  Motor,  The 10 

Duncan  on  Alternating  Currents    .         .         .  262 

Duncan  Motor,  The  Alternating     .         .         .  262 

Dynamos,  Reversibility  of,  observed        .         .  29 

Eddy  Motor,  The 306 

Edgerton  Motor,  The 192 

Edison's  Electric  Railway       .         .         .68,  69,  70 

Edison  Motor,  The                  ....  302 


312 


INDEX. 


PAGE 

Edison  Thermo-Magnetic  Motor,  .  .  .274 
"  Electricity,"  Launch,  The  .  .  .  .137 
Electro-Dynamic  Rotation  (Ferraris)  .  .  271 

Elias  Motor,  The 9 

Elieson  Motor,  with  Storage,  The  .  .  .109 
Elwell-Parker  Generator,  The  .  .  .59,  GO 

Esteve  Motor,  The 116 

Farmer  Motor,  The  .  .  .  .  .  20 
Ferraris  on  Electro-Dynamic  Rotation  .  .  271 
Field's  Electric  Railway  .  .  .  01,  185 

Field  of  Force 2 

Field  Road,  New  York  City  .  .  .  .  204 
Field  Street  Railway  System  ....  206 
Fisher  Motor,  The  .  .  .  .  194,215 

Fisher  Road,  Detroit,  Mich 214 

Frankfort  Electric  Railway,  'The    .         .         .         50 

Froment  Motor,  The 10 

Gaume  Motor,  The 24 

Generators : 

Daft ..129 

Deprez     .        .         .         .        .         .         .         41 

Deprez,  at  Creil       .         .        .         .         .         41 

Elwell-Parker 59 

Siemens  .......         48 

Van  Depoele    ......         93 

Victoria .6 

Gilbert  on  the  Pyromagnetic  Principle  .  .  272 
Glynde,  Eng.,  The  Telpher  Road  .  .  144 

Gore  on  Pyromagnetism          ....       272 

Gramme  Motor,  The 121 

Griscom  Motor,  The 125 

Gustin  Motor,  The  ...  .18 
Hall  Motor,  The  .  .  20 

Hamburg  Electric  Railway,  The  (Storage)  .  Ill 
Henry's  Electric  Railway  .  .  .  .181 
Henry  Motor,  The  .  .  .181 
Hering  on  the  Theory  of  Pyromagnetic  Gener- 
ators .  ....  278 
Higham  Motor,  The  .  .  .  .182 
Hochhausen  Motor,  The  .  .241 
Hopkinson  on  Alternate-Current  Motors  .  255 
Hyer  Motor,  The  ....  .241 
Immisch  Motor,  The  .  .  248 
Irish's  Railway,  Conduit  System  .  .  .  216 
Jablochkoff  Motor,  The  .  114 
Jacobi  Motor,  The  .  8,  9 
Jacobi's  Law  .  .... 
"Judge,"  The  .  63 

Julien  Accumulator  and  Traction  System,  The  224 
Julien  Storage  Car  System,  New  York  .  .  224 
Keegan  Motor,  The 134 


Kew  Bridge,  London,  Electric  Railway,  The 

(Storage) 100 

Krebs-Renard  Balloon,  The    ....  140 

Kriegstetten-Solothurn  Power  Transmission  .  252 

Lartigue  Electric  Railway       ....  59 

Launch  "Electricity,"  The     ....  137 

Launch,  Trouve,  The 137 

Launch  "  Volta,"  The 138 

Lee-Chaster  Motor,  The          ....  122 

Lenz's  Law .  3 

Lichterfelde  Electric  Railway,  The         .         .  50 

Lillie  Motor,  The 16 

Lilley  and  Colton  Motor,  f  he         ...  28 

Lodge  on  Pyromagnetism       ....  272 

London  Electric  Railway,  The  (Storage)         .  101 

Lugo  Motor,  The 236 

Mason  Motor,  The 26 

McCullough  Motor,  The         ....  23 

McGee  Pyromagnetic  Motor  ....  272 

Menges  Pyromagnetic  Motor  ....  276 

Millwall  Electric  Railway,  The  (Storage)        .  103 

Minneapolis  Electric  Railway,  The         .         .  97 

Montgomery,  Ala.,  Electric  Railway,  The      .  97 

Mordey's  Experiment     .....  5 

"  Morse,"  The        .        .         .         .         .         .  74 

Motor,  The  Avery 17 

"         "     Ayrton-Perry       .         .         .         .122 

"    Baxter         .....  227 

"    Beattie 153 

"         "    Botto 8 

"         "     Bourbouze  .....  11 
"     Brown  (Oerlikon)        .         .         .251 

"         "     Brush 154 

"     C.  &  C.        .'       .         .         .         .230 

"     Card 242 

"     Connecticut         .         .         .         .306 

"     Cook 15 

"         "     Crocker-Wheeler          .         .         .303 
"         "     Curtis  &  Crocker          .         .         .155 

"    Daft 127 

"         "     Davenport 13 

"         "     Davidson     .         .         .         .         .  9 

"     De  Morat 26 

"         "     Deprez 115 

"     Diehl 133,  244 

"     Du  Moncel           ....  10 

"         "     Duncan  (Alternating  Current)    .  262 

•'     Eddy 306 

"        "    Edgerton 192 

"         "     Edison 302 

"         "     Elias   .  9 


INDEX. 


313 


Motor,  The 


PAGE 

PAGE 

Elieson,  with  Storage 

109 

Motor,  The  Walkly        

14 

Esteve 

.       116 

"         "     Wickersham         .... 

25 

Farmer 

20 

"     Yeiser          

23 

Field  . 

.       185 

Munich  Exposition,  Motors  at  the  . 

31 

194,  215 

Munich,  Transmission  of  Energy  at,  by  Deprez 

31-39 

10 

Neff  Motor,  The     

16 

Gaume 

24 

New  Orleans  Electric  Railway,  The 

73 

Gramme 

.       121 

tt          tt            tt            t<             tt 

97 

Griscom       .... 

.       125 

New  York  District  Railway,  The    . 

83 

18 

New  York  Elevated  Railroad,  Tests  on  the      7: 

3,  180 

Hall    . 

20 

Operation  of  Motors  from  Electric  Light  and 

Henry 

.       181 

Power  Stations          .... 

196 

Higham       .... 

.       182 

Oersted's  Experiment     .... 

1 

Hochhausen 

.       241 

Pacinotti  Motor,  The      . 

11 

241 

Page  Motor,  The    

19-21 

248 

28 

TahlAftKlrAff 

114 

238 

U  UUUJCJlQ-Ull                  •                 • 

8,  9 

Patten  Motor  (Alternating),  The  . 

262 

134 

Paris  Electric  Railway,  The    .... 

55 

Lee-Chaster 

.       122 

"           "             "             "     (Storage)    . 

101 

Lillie 

16 

Pendleton   Method   of   Attaching    Motors  to 

Lilley  and  Colton 

28 

Street  Cars,  The    .... 

98 

236 

Pendleton  Motor,  The    ..... 

134 

Mason 

26 

Perret  Motor,  The          

308 

McCullough 

23 

Pinkus  Motor,  The      

28 

Neff 

16 

Pollak  and  Bingswanger  Conduit  Road  . 

247 

Pacinotti     .... 

11 

Portrush  Electric  Railway,  The 

48 

Page    

.  19-21 

Printing  The  Electrical  World  by  Electricity  . 

129 

28 

Rae,  T.  W.,  on  size  of  Conductor  . 

44 

Patten          .... 

.       238 

Rae,  Electric  Railway  System,  The 

286 

Patten  (Alternating  Current) 

.       260 

Railway,  The  Antwerp  Electric  (Storage) 

104 

Pendelton  (Method)    . 

98 

"           "     Baltimore  Electric    . 

73 

Pendleton, 

.       134 

"           "             "               "         (Storage)     . 

108 

Perret          .... 

.       308 

"           '      Beutley-Knight  Electric,  Cleve- 

Pinkus        .... 

28 

land    ..... 

81 

Reckenzaun 

.       118 

"           "     Bentley-Knight,      Woonsocket, 

Salvatore  dal  Negro    . 

8 

R.  I.             ... 

200 

Schlesinger 

190,  220 

"           "     Bentley-Knight,  Allegheny  City, 

Schulthess  . 

8 

Pa.      . 

201 

Spragtie       .... 

.       15G 

"          "    Berlin,  Electric 

48 

Stein            .... 

21 

"           "         "             "      (Storage)    . 

103 

Stimpson     .... 

14 

"           "     Besspool  Electric 

59 

Stock  well    .... 

.       152 

"           "     Blackpool  Electric    . 

55 

Tesla  (Alternating  Current) 

.       264 

"           "     Breuil-en-Auge  Electric   . 

100 

Thomson     .... 

1!>7,  226 

"           "     Brighton  Electric     . 

55 

Thomson,  E.  (Altg.  Current) 

.       260 

"           "     Chicago  Electric 

62 

Thone          .... 

.       242 

"           "     City  and  South  London  Electric 

United  States 

.       307 

Railway,  The     . 

298 

Van  Depoele 

94 

"     Cleveland  Electric    . 

81 

"         "               ... 

132,  183 

"           "     Coney  Island  Electric 

73 

Vergnes       .... 

22 

"           "     Daft  Electric   .... 

70 

314 


INDEX. 


Railway,  The  Drybrook-Mine  Electric  (Storage)  110 
"           "     Edison  Electric  (Menlo  Park)  68,  69,70 

"           "     Electric,  Details  of  the  Modern  300 

"           "     Field  Electric  (Early)        .         .  61 

"           "     Field,  New  York  City       .         .  204 

"          "    Field,  Street  Railway        .         .  206 

•  "          "    Fisher,  Detroit,  Mich.      .         .  214 

"           "     Frankfort,  Electric  ...  50 

"           "     Hamburg  Electric  (Storage)      .  Ill 

"          "     Henry  Electric         ...  181 
"     Irish's  Conduit  System      .         .216 

"           "     Julien  Electric,  in  New  York  .  200 

"          "    Kew  Bridge  Electric  (London)  100 

"          "     Lartigue  Electric       .                 .  59 

"          "    Lichterfelde  Electric         .         .  50 

"          "     London  Electric  (Storage)  101 

"          "     Millwali  Electric  (Storage)       .  103 

"          "     Minneapolis  Electric         .         .  97 

"           "     Montgomery,  Ala.,  Electric      .  97 

"          "     New  Orleans  Electric        .         .  73 

tt              a        «             «                u  gij< 

"          "    Paris  Electric 55 

"           "         "          "     (Storage)       .         .  101 

"          "     Pollak  and  Binswanger    .         .  247 

"           "     Portrush  Electric      ...  48 

"           "     Schlesinger  Electric  (Phila.)     .  190 
"           "     Schlesinger,  Lykens  Valley  Coal 

Mine 218 

"          "    Siemens  System        .        .        .  48 

"           "     Short-Nesmith,  Denver,  Col.    .  209 

"          "     South  Bend  Electric         .         .  97 

"           "     Sprague  Electric  (New  York)  .  168 

"           "     Toronto  Electric       ...  94 

"          "     Vienna  Electric  (Proposed)       .  52 

"           "           "             "       (Exposition)    .  55 

"          "     Windsor,  Ont.,  Electric    .         .  98 

"          "    Zankeroda  Electric  ...  48 

Reckenzaun  Launches,  The    ....  138 

Reckenzaun  Motor,  The         ....  118 

Reversibility  of  Dynamos  observed          .         .  29 

Ries  System  of  Conduited  Mains     .         .         .  195 

Riveting-Machine,  The  Rowan        .         .         .  249 

Rowan  Calking-Machine         ....  250 

Rowan  Chipping-Machine       .         .                  .  250 

Rowan  Drilling-Machine        ....  249 

Rowan  Riveting-Machine        .         .                  .  249 

Salvatore  dal  Negro  Motor,  The     .  8 

Schlesinger  Motor,  The          .                          .  220 

Schlesinger  Lykens  Valley  Road     .         .         .  218 

Schlesinger  on  Transmission  of  Power  . 

Schlesinger  Street  Railway  System          .        .  190 


PAGE 

SchwedofE  Thermo-Magnetic  Motor  .  .  273 
Siemens  Railway  System,  The  ...  48 
Short-Nesmith,  Denver,  Col.,  Road  .  .  209 
Short  Gearless  Railway  Motor,  The  .  .  296 
Short  Railway  Motor,  The  .  .  .  .282 
South  Bend  Electric  Railway,  The  .  .  97 
Sprague  Electric  Railway,  .  .  .  .168 
Sprague  Electric  Railway  Motors,  The  .  .  279 
Sprague  Motor,  The  .....  156 

Stein  Motor,  The 21 

Stockwell  Motor,  The 152 

Stimpson  Motor,  The     .....         14 

Secondary  Batteries  witli  Motors    ...         99 
'•  "          Antwerp  Tramway  Motor 

Tests         .         .         .104 
"  "          Baltimore  Tramway  Mo- 

tor Tests  .         .         .108 
"  "          Berlin    Tramway    Motor 

Tests          .         .         .103 
"  "          Breuil-en-Auge  Railway         100 

"  "          Dover-Calais    Voyage    of 

the  "  Volta"    .         .       138 
"  "          Dry  brook  Mine  Locomo- 

tive  ....       110 

"  "         Elieson  Tramway    .         .       109 

"  "          Hamburg  Electric  Railway     111 

"  "          Julien  System  in  N.  Y.   .       224 

"  "          Kew  Bridge  Tramway     .       100 

"  "          Krebs-Renard  Balloon     .       140 

"  "          Launch  "  Electricity "    .       137 

"  "          London  Electric  Railway       101 

"  "          Millwali  Electric  Railway       103 

"  "          Paris  Electric  Railway    .       101 

"  "          Reckenzaun  Launches     .       118 

"  "         Yarrow  Launch  of  1883        137 

Taverdon  Drill  with  Gramme  Motor,  The       .       121 
Telpherage      .......       146 

"          Telpher  Road,  Glynde,  Eng.         .       144 
"  "          "      Weston,  Eng.         .       144 

"  "       System,  Fleeming  Jenkin, 

The  ....       143 

"  "       System,  Chandler,  The          148 

•'  "  "       Van  Depoele,  The      150 

Tesla  Motor,  the  Alternating          .         .         .       204 
Thermo-Magnetic  Motors  : 

Berliner  ....  .278 

Edison     .         .         .         .         .         .         .274 

McGee     .....  .273 

Menges    .......      276 

Schwedoff 274 

Thomson  and  Houston     ....       272 


INDEX. 


315 


10: 


Thomson,  E.,  on  Alternating  Currents  . 
Thomson  and  Houston  Pyromagnetic  Motor 
Thomson-Houston  Railway  Motor,  The 
Thomson-Houston  Slow  Speed  Railway  Motor, 

The 

Thomson,  Sir  W.,  on  Size  of  Conductor 
Thomson  Motor,  The 
Thone  Motor,  The 
Tissandier  Balloon,  The 
Toronto  Electric  Railway,  The 
Transmission  at  Munich  by  Deprez 

"  Grenoble  by  Deprez 
"          "  Creil  by  Deprez     . 
Trouve  Launch,  The 
United  States  Motor,  The 
Van  Depoele  Generator,  The 
Van  Depoele  Motor,  The 


PAGE  PAGE 

256  Van  Depoele  Telpher  System,  The  .  .  150 

272  Vergnes  Motor,  The 22 

281  Victoria  Dynamo    ......  6 

Vienna  Electric  Railway,  The  (Proposed)  .  52 

291  "  "  "  "  (Exposition)  .  55 

47  "Volta"  Launch,  The 138 

j  226  Walkly  Motor,  The U 

242  Wenstrom  Railway  System,  The  .  .  .  287 

138  Westinghouse  Gearless  Railway  Motor,  The  .  296 

94  Westinghouse  Railway  Motor,  The  .  .  283 

.31-39  Westinghouse  Slow  Speed  Railway  Motor,  The  294 

41  Weston,  Eng.,  The  Telpher  Road  .         .         .144 

41  Wickersham  Motor,  The  ....  25 

137  Wilde's  Alternating  Current  Experiments  .  255 

307  Windsor,  Ont.,  Electric  Railway,  The  .  .  98 

93  Yeiser  Motor,  The 23 

94  Yarrow  Launch  of  1883  .        .        .        .137 
132,  183  Zankeroda  Electric  Railway,  The    .        .  48 


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